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Full vulnerability report · 2026
CVE-2026-78510High confidence

Microsoft Outlook and Word Remote Code Execution Vulnerability

Microsoft · Microsoft 365 Apps for Enterprise

8.4HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityHighOperational priority:High, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 0.34% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict local access and enforce least privilege on affected hosts.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Microsoft Microsoft 365 Apps for Enterprise and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 30 daysRemediation target: Within 180 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
msrc_CVE-2026-78510 · CSAF 2.0 · revision 4 · finalMicrosoft Security Response CenterMicrosoft Outlook and Word Remote Code Execution Vulnerability
13 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • Microsoft Office 365 for Mac <16.113.26091433
  • Microsoft Office LTSC for Mac 2024 <16.113.26091433
  • Microsoft Office LTSC 2024 for 64-bit editions <16.0.17932.20976
  • Microsoft Office LTSC 2024 for 32-bit editions <16.0.17932.20976
  • Microsoft Office LTSC 2021 for 32-bit editions <16.0.14334.20906
  • Microsoft Office LTSC 2021 for 64-bit editions <16.0.14334.20906
  • Microsoft Office LTSC for Mac 2021 <16.113.26091433
  • Microsoft 365 Apps for Enterprise for 64-bit Systems <16.0.20326.20138
  • Microsoft 365 Apps for Enterprise for 32-bit Systems <16.0.20326.20138
  • Microsoft Office 2019 for 64-bit editions <16.0.10417.20207
  • Microsoft Office 2019 for 32-bit editions <16.0.10417.20207
  • Microsoft Office 2016 (64-bit edition) <16.0.5569.1000
Summary
Microsoft
Remediation
16.0.10417.20207:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-73308

No EUVD known-exploited evidence

Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
8.4 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.

What

Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.

Why

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

How

An attacker operating through local access may attempt exploitation without authentication or user interaction. If successful, the issue may execute code or commands in the affected security context.

What

Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.

Why

A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

How

An attacker operating through local access may attempt exploitation without authentication or user interaction. If successful, the issue may execute code or commands in the affected security context.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
local access → Heap-based Buffer Overflow → execute code or commands in the affected security context
Attack surface
Local
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-122 ↗

CWE-122: Heap-based Buffer Overflow. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
UnauthenticatedRemote code executionCWE-122
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-73308Official EUVD mapping

Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.

Official EUVD record ↗
BSI · German · WID-SEC-2026-3234Microsoft Office Produkte: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in verschiedenen Microsoft Office Produkten, Microsoft Office Online Server, Microsoft 365 Apps, Microsoft SharePoint, Microsoft Teams und Microsoft Skype ausnutzen, um erhöhte Berechtigungen zu erlangen, um Code auszuführen, um Informationen offenzulegen und um den Nutzer zu täuschen.

Official advisory ↗
INCIBE-CERT · Spanish · boletin-de-seguridad-de-microsoft-septiembre-de-2026Boletín de seguridad de Microsoft: septiembre de 2026

ad de Ejecución Remota de Código en Internet Connection Sharing (ICS) CVE-2026-73009: vulnerabilidad de Ejecución Remota de Código en Windows Secure Socket Tunneling Protocol (SSTP) CVE-2026-73010: vulnerabilidad de Ejecución Remota de Código en Microsoft Failover Cluster CVE-2026-73025: vulnerabilidad de Omisión de Característica de Seguridad en Windows iSCSI CVE-2026-77493: vulnerabilidad de Ejecución Remota de Código en Windows Graphics Component CVE-2026-78445: vulnerabilidad de Ejecución Remota de Código en Windows Services for NFS ONCRPC XDR Driver CVE-2026-78509: vulnerabilidad de Ejecución Remota de Código en Microsoft Office Outlook CVE-2026-78510: vulnerabilidad de Ejecución Remota de Código en Microsoft Word CVE-2026-80098: vulnerabilidad de Elevación de Privilegios en Copilot Studio CVE-2026-81376: vulnerabilidad de Omisión de Característica de Seguridad en Visual Studio Code CVE-2026-81963: vulnerabilidad de Elevación de Privilegios en Windows Update Stack (Está siendo explotada) CVE-2026-83711: vulnerabilidad de Elevación de Privilegios en Microsoft Azure Active Directory B2C CVE-2026-83941: vulnerabilidad de Elevación de Privilegios en Entra ID CVE-2026-85880: vulnerabilidad de Elevación de Privilegios en Windows Advanced Local Procedure Call (ALPC) (Está siendo explotada) Los c

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-1145Multiples vulnérabilités dans Microsoft Office

u 08 septembre 2026 Bulletin de sécurité Microsoft Office CVE-2026-78439 du 08 septembre 2026 Bulletin de sécurité Microsoft Office CVE-2026-78502 du 08 septembre 2026 Bulletin de sécurité Microsoft Office CVE-2026-78503 du 08 septembre 2026 Bulletin de sécurité Microsoft Office CVE-2026-78504 du 08 septembre 2026 Bulletin de sécurité Microsoft Office CVE-2026-78505 du 08 septembre 2026 Bulletin de sécurité Microsoft Office CVE-2026-78506 du 08 septembre 2026 Bulletin de sécurité Microsoft Office CVE-2026-78507 du 08 septembre 2026 Bulletin de sécurité Microsoft Office CVE-2026-78509 du 08 septembre 2026 Bulletin de sécurité Microsoft Office CVE-2026-78510 du 08 septembre 2026 Bulletin de sécurité Microsoft Office CVE-2026-78511 du 08 septembre 2026 Bulletin de sécurité Microsoft Office CVE-2026-78512 du 08 septembre 2026 Bulletin de sécurité Microsoft Office CVE-2026-78513 du 08 septembre 2026 Bulletin de sécurité Microsoft Office CVE-2026-78514 du 08 septembre 2026 Bulletin de sécurité Microsoft Office CVE-2026-78515 du 08 septembre 2026 Bulletin de sécurité Microsoft Office CVE-2026-78517 du 08 septembre 2026 Bulletin de sécurité Microsoft Office CVE-2026-78518 du 08 septembre 2026 Bulletin de sécurité Microsoft Office CVE-2026-78519 du 08 septembre 2026 Bulletin de sécurité Microsoft Offic

Official advisory ↗
CSIRT Italia · Italian · aggiornamenti-mensili-microsoft-24Aggiornamenti Mensili Microsoft

nuova finestra - - CVE-2026-81953 : apre una nuova finestra - - CVE-2026-83972 : apre una nuova finestra - - CVE-2026-81952 : apre una nuova finestra - - CVE-2026-83973 : apre una nuova finestra - - CVE-2026-85877 : apre una nuova finestra - - CVE-2026-81951 : apre una nuova finestra - - CVE-2026-83974 : apre una nuova finestra - - CVE-2026-78515 : apre una nuova finestra - - CVE-2026-78516 : apre una nuova finestra - - CVE-2026-78517 : apre una nuova finestra - - CVE-2026-78518 : apre una nuova finestra - - CVE-2026-78519 : apre una nuova finestra - - CVE-2026-83948 : apre una nuova finestra - - CVE-2026-83949 : apre una nuova finestra - - CVE-2026-78510 : apre una nuova finestra - - CVE-2026-78511 : apre una nuova finestra - - CVE-2026-78512 : apre una nuova finestra - - CVE-2026-78513 : apre una nuova finestra - - CVE-2026-78514 : apre una nuova finestra - - CVE-2026-81400 : apre una nuova finestra - - CVE-2026-83942 : apre una nuova finestra - - CVE-2026-83940 : apre una nuova finestra - - CVE-2026-81401 : apre una nuova finestra - - CVE-2026-83941 : apre una nuova finestra - - CVE-2026-78526 : apre una nuova finestra - - CVE-2026-78520 : apre una nuova finestra - - CVE-2026-78521 : apre una nuova finestra - - CVE-2026-78522 : apre una nuova finestra - - CVE-2026-78523 : apre una nuova fi

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6946MS 9월 보안 위협에 따른 정기 보안 업데이트 권고

| | Microsoft Office Word | CVE-2026-78502 | Microsoft Office Word 정보 공개 취약성 | | Microsoft Office Word | CVE-2026-78503 | Microsoft Office Word 정보 공개 취약성 | | Microsoft Office Word | CVE-2026-78504 | Microsoft Office Word 원격 코드 실행 취약성 | | Microsoft Office | CVE-2026-78505 | Microsoft Office 원격 코드 실행 취약성 | | Microsoft Office Word | CVE-2026-78506 | Microsoft Office Word 정보 공개 취약성 | | Microsoft Office Word | CVE-2026-78507 | Microsoft Office Word 원격 코드 실행 취약성 | | Windows CD-ROM Driver | CVE-2026-78508 | Windows CD-ROM 드라이버 정보 유출 취약성 | | Microsoft Office Outlook | CVE-2026-78509 | Microsoft Office Outlook 원격 코드 실행 취약성 | | Microsoft Office Word | CVE-2026-78510 | Microsoft Word 원격 코드 실행 취약성 | | Microsoft Office Word | CVE-2026-78511 | Microsoft Office Word 원격 코드 실행 취약성 | | Microsoft Office Word | CVE-2026-78512 | Microsoft Office Word 원격 코드 실행 취약성 | | Microsoft Office PowerPoint | CVE-2026-78513 | Microsoft Office PowerPoint 정보 유출 취약성 | | Microsoft Office Word | CVE-2026-78514 | Microsoft Office Word 원격 코드 실행 취약성 | | Microsoft Office Excel | CVE-2026-78515 | Microsoft Office Excel 정보 유출 취약성 | | Windows Storage | CVE-2026-78516 | Windows 저장소 정보 유출 취약성 | | Microsoft Office Word | CVE-2026-78517 | Microsoft Office Word 원격 코드 실행 취약성 | | Microsoft Office Excel | CVE-2026-78518 | Microsoft Office Excel 원

Official advisory ↗
NCSC-NL · Dutch · NCSC-2026-0352Kwetsbaarheden verholpen in Microsoft Office

Een kwaadwillende kan de kwetsbaarheden misbruiken om aanvallen uit te voeren die kunnen leiden tot de categorieën schade, zoals genoemd in onderstaande tabel. Voor succesvol misbruik moet de kwaadwillende het slachtoffer misleiden een malafide bestand te openen of link te volgen. Microsoft heeft voor Office 114 kwetsbaarheden verholpen. De 4 ernstigste kwetsbaarheden bevinden zich in meerdere Office componenten en hebben een CVSS score van 9.8 toegewezen gekregen. Kwaadwillenden met toegang tot deze componenten kunnen zonder voorafgaande authenticatie mogelijk code uitvoeren of zich toegang verschaffen tot het kwetsbare systeem. Deze kwetsbaarheden zijn in onderstaande tabel weergegeven. De overige 110 kwetsbaarheden variëren in ernst van middelmatig tot hoog en kritiek. Raapleeg het MSRC-portaal voor aanvullende informatie. ``` |----------------|------|---------------------------|-------------------------------------| | CVE-ID | CVSS | Component | Impact | |----------------|------|---------------------------|-------------------------------------| | CVE-2026-78505 | 9,80 | Office | Uitvoeren van willekeurige code | |----------------|------|---------------------------|-------------------------------------| | CVE-2026-78509 | 9,80 | Outlook | Uitvoeren van willekeurige code | |----------------|------|---------------------------|-------------------------------------| | CVE-2026-78510 | 9,80 | Outlook | Uitvoeren van willekeurige code | |----------------|------|---------------------------|-------------------------------------| | CVE-2026-66302 | 9,80 | SKYPE | Uitvoeren van willekeurige code | |----------------|------|---------------------------|-------------------------------------| ```

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Fixed
Action
16.0.10417.20207:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 8 Sept 2026 · Last source change 1 Oct 2026, 22:55 UTC · CWE-122 · Heap-based Buffer Overflow

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-09-09
European sourceENISA EUVD · EUVD-2026-73308
Product sourceVendor CSAF · Microsoft Security Response Center
Remediation sourceVendor CSAF · Microsoft Security Response Center
CWE sourceOther authority
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    Microsoft 365 Apps for Enterprise: 16.0.1 < 16.0.20326.20138; Microsoft Office 2016: 16.0.0 < 16.0.5569.1000; Microsoft Office 2019: 19.0.0 < 16.0.10417.20207; Microsoft Office 365 for Mac: 1.0.0 < 16.113.26091433; Microsoft Office LTSC 2021: 16.0.1 < 16.0.14334.20906; Microsoft Office LTSC 2024: 16.0.0 < 16.0.17932.20976; Microsoft Office LTSC for Mac 2021: 16.0.1 < 16.113.26091433; Microsoft Office LTSC for Mac 2024: 16.0.0 < 16.113.26091433 · Fixed: 16.0.10417.20207:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
    After
    Microsoft 365 Apps for Enterprise: 16.0.1 < 16.0.20326.20138; Microsoft Office 2016: 16.0.0 < 16.0.5569.1000; Microsoft Office 2019: 19.0.0 < 16.0.10417.20207; Microsoft Office 365 for Mac: 1.0.0 < 16.113.26091433; Microsoft Office LTSC 2021: 16.0.1 < 16.0.14334.20906; Microsoft Office LTSC 2024: 16.0.0 < 16.0.17932.20976; Microsoft Office LTSC for Mac 2021: 16.0.1 < 16.113.26091433; Microsoft Office LTSC for Mac 2024: 16.0.0 < 16.113.26091433 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    CNA ↗
  2. Affected versionsThe structured affected or fixed version information changed.
    Before
    Microsoft 365 Apps for Enterprise: 16.0.1 < 16.0.20326.20138; Microsoft Office 2016: 16.0.0 < 16.0.5569.1000; Microsoft Office 2019: 19.0.0 < 16.0.10417.20207; Microsoft Office 365 for Mac: 1.0.0 < 16.113.26091433; Microsoft Office LTSC 2021: 16.0.1 < 16.0.14334.20906; Microsoft Office LTSC 2024: 16.0.0 < 16.0.17932.20976; Microsoft Office LTSC for Mac 2021: 16.0.1 < 16.113.26091433; Microsoft Office LTSC for Mac 2024: 16.0.0 < 16.113.26091433 · Fixed: 16.0.10417.20207:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
    After
    Microsoft 365 Apps for Enterprise: 16.0.1 < 16.0.20326.20138; Microsoft Office 2016: 16.0.0 < 16.0.5569.1000; Microsoft Office 2019: 19.0.0 < 16.0.10417.20207; Microsoft Office 365 for Mac: 1.0.0 < 16.113.26091433; Microsoft Office LTSC 2021: 16.0.1 < 16.0.14334.20906; Microsoft Office LTSC 2024: 16.0.0 < 16.0.17932.20976; Microsoft Office LTSC for Mac 2021: 16.0.1 < 16.113.26091433; Microsoft Office LTSC for Mac 2024: 16.0.0 < 16.113.26091433 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    CNA ↗
  3. Affected versionsThe structured affected or fixed version information changed.
    Before
    Microsoft 365 Apps for Enterprise: 16.0.1 < 16.0.20326.20138; Microsoft Office 2016: 16.0.0 < 16.0.5569.1000; Microsoft Office 2019: 19.0.0 < 16.0.10417.20207; Microsoft Office 365 for Mac: 1.0.0 < 16.113.26091433; Microsoft Office LTSC 2021: 16.0.1 < 16.0.14334.20906; Microsoft Office LTSC 2024: 16.0.0 < 16.0.17932.20976; Microsoft Office LTSC for Mac 2021: 16.0.1 < 16.113.26091433; Microsoft Office LTSC for Mac 2024: 16.0.0 < 16.113.26091433 · Fixed: 16.0.10417.20207:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
    After
    Microsoft 365 Apps for Enterprise: 16.0.1 < 16.0.20326.20138; Microsoft Office 2016: 16.0.0 < 16.0.5569.1000; Microsoft Office 2019: 19.0.0 < 16.0.10417.20207; Microsoft Office 365 for Mac: 1.0.0 < 16.113.26091433; Microsoft Office LTSC 2021: 16.0.1 < 16.0.14334.20906; Microsoft Office LTSC 2024: 16.0.0 < 16.0.17932.20976; Microsoft Office LTSC for Mac 2021: 16.0.1 < 16.113.26091433; Microsoft Office LTSC for Mac 2024: 16.0.0 < 16.113.26091433 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    CNA ↗
  4. Affected versionsThe structured affected or fixed version information changed.
    Before
    Microsoft 365 Apps for Enterprise: 16.0.1 < 16.0.20326.20138; Microsoft Office 2016: 16.0.0 < 16.0.5569.1000; Microsoft Office 2019: 19.0.0 < 16.0.10417.20207; Microsoft Office 365 for Mac: 1.0.0 < 16.113.26091433; Microsoft Office LTSC 2021: 16.0.1 < 16.0.14334.20906; Microsoft Office LTSC 2024: 16.0.0 < 16.0.17932.20976; Microsoft Office LTSC for Mac 2021: 16.0.1 < 16.113.26091433; Microsoft Office LTSC for Mac 2024: 16.0.0 < 16.113.26091433 · Fixed: 16.0.10417.20207:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
    After
    Microsoft 365 Apps for Enterprise: 16.0.1 < 16.0.20326.20138; Microsoft Office 2016: 16.0.0 < 16.0.5569.1000; Microsoft Office 2019: 19.0.0 < 16.0.10417.20207; Microsoft Office 365 for Mac: 1.0.0 < 16.113.26091433; Microsoft Office LTSC 2021: 16.0.1 < 16.0.14334.20906; Microsoft Office LTSC 2024: 16.0.0 < 16.0.17932.20976; Microsoft Office LTSC for Mac 2021: 16.0.1 < 16.113.26091433; Microsoft Office LTSC for Mac 2024: 16.0.0 < 16.113.26091433 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    CNA ↗
  5. SeveritySeverity changed from Critical to High.
    Before
    Critical
    After
    High
    CNA ↗
  6. CVSS scoreCVSS score changed from 9.8 (CVSS 3.1 · CNA · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C) to 8.4 (CVSS 3.1 · CNA · CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C).
    Before
    9.8 (CVSS 3.1 · CNA · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C)
    After
    8.4 (CVSS 3.1 · CNA · CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C)
    CNA ↗
  7. Affected versionsThe structured affected or fixed version information changed.
    Before
    Microsoft 365 Apps for Enterprise: 16.0.1 < 16.0.20326.20138; Microsoft Office 2016: 16.0.0 < 16.0.5569.1000; Microsoft Office 2019: 19.0.0 < 16.0.10417.20207; Microsoft Office 365 for Mac: 1.0.0 < 16.113.26091433; Microsoft Office LTSC 2021: 16.0.1 < 16.0.14334.20906; Microsoft Office LTSC 2024: 16.0.0 < 16.0.17932.20976; Microsoft Office LTSC for Mac 2021: 16.0.1 < 16.113.26091433; Microsoft Office LTSC for Mac 2024: 16.0.0 < 16.113.26091433 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    After
    Microsoft 365 Apps for Enterprise: 16.0.1 < 16.0.20326.20138; Microsoft Office 2016: 16.0.0 < 16.0.5569.1000; Microsoft Office 2019: 19.0.0 < 16.0.10417.20207; Microsoft Office 365 for Mac: 1.0.0 < 16.113.26091433; Microsoft Office LTSC 2021: 16.0.1 < 16.0.14334.20906; Microsoft Office LTSC 2024: 16.0.0 < 16.0.17932.20976; Microsoft Office LTSC for Mac 2021: 16.0.1 < 16.113.26091433; Microsoft Office LTSC for Mac 2024: 16.0.0 < 16.113.26091433 · Fixed: 16.0.10417.20207:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
    Microsoft Security Response Center ↗
  8. Affected versionsThe structured affected or fixed version information changed.
    Before
    Microsoft 365 Apps for Enterprise: 16.0.1 < 16.0.20326.20138; Microsoft Office 2016: 16.0.0 < 16.0.5569.1000; Microsoft Office 2019: 19.0.0 < 16.0.10417.20207; Microsoft Office 365 for Mac: -; Microsoft Office LTSC 2021: 16.0.1 < 16.0.14334.20906; Microsoft Office LTSC 2024: 16.0.0 < 16.0.17932.20976; Microsoft Office LTSC for Mac 2021: -; Microsoft Office LTSC for Mac 2024: - · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    After
    Microsoft 365 Apps for Enterprise: 16.0.1 < 16.0.20326.20138; Microsoft Office 2016: 16.0.0 < 16.0.5569.1000; Microsoft Office 2019: 19.0.0 < 16.0.10417.20207; Microsoft Office 365 for Mac: 1.0.0 < 16.113.26091433; Microsoft Office LTSC 2021: 16.0.1 < 16.0.14334.20906; Microsoft Office LTSC 2024: 16.0.0 < 16.0.17932.20976; Microsoft Office LTSC for Mac 2021: 16.0.1 < 16.113.26091433; Microsoft Office LTSC for Mac 2024: 16.0.0 < 16.113.26091433 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    CNA ↗
  9. Affected versionsThe structured affected or fixed version information changed.
    Before
    16.0.1 < 16.0.20326.20138; 16.0.0 < 16.0.5569.1000; 19.0.0 < 16.0.10417.20207; -; 16.0.1 < 16.0.14334.20906; 16.0.0 < 16.0.17932.20976 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    After
    Microsoft 365 Apps for Enterprise: 16.0.1 < 16.0.20326.20138; Microsoft Office 2016: 16.0.0 < 16.0.5569.1000; Microsoft Office 2019: 19.0.0 < 16.0.10417.20207; Microsoft Office 365 for Mac: -; Microsoft Office LTSC 2021: 16.0.1 < 16.0.14334.20906; Microsoft Office LTSC 2024: 16.0.0 < 16.0.17932.20976; Microsoft Office LTSC for Mac 2021: -; Microsoft Office LTSC for Mac 2024: - · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    CNA ↗
  10. ENISA EUVD mappingEUVD-2026-73308 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-73308"}
    ENISA EUVD ↗
  11. Vendor guidanceAuthoritative vendor guidance changed: added patch: msrc.microsoft.com/CVE-2026-78510; added remediation: msrc.microsoft.com/CVE-2026-78510.
    Before
    no authoritative guidance recorded
    After
    patch: msrc.microsoft.com/CVE-2026-78510 · remediation: msrc.microsoft.com/CVE-2026-78510
    secure@microsoft.com ↗
  12. Affected versionsThe structured affected or fixed version information changed.
    Before
    16.0.1 < 16.0.20326.20138; 16.0.0 < 16.0.5569.1000; 19.0.0 < 16.0.10417.20207; -; 16.0.1 < 16.0.14334.20906; 16.0.0 < 16.0.17932.20976 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    16.0.1 < 16.0.20326.20138; 16.0.0 < 16.0.5569.1000; 19.0.0 < 16.0.10417.20207; -; 16.0.1 < 16.0.14334.20906; 16.0.0 < 16.0.17932.20976 · Fixed: An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
    CNA ↗
  13. Remediation statusRemediation status changed from Awaiting fix to Patch available.
    Before
    Awaiting fix
    After
    Patch available
    secure@microsoft.com ↗
  14. Affected versionsThe structured affected or fixed version information changed.
    Before
    16.0.1 < 16.0.20326.20136; 16.0.0 < 16.0.5569.1000; 19.0.0 < 16.0.10417.20204; -; 16.0.1 < 16.0.14334.20896; 16.0.0 < 16.0.17932.20960 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    16.0.1 < 16.0.20326.20138; 16.0.0 < 16.0.5569.1000; 19.0.0 < 16.0.10417.20207; -; 16.0.1 < 16.0.14334.20906; 16.0.0 < 16.0.17932.20976 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
  15. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release or patch reference recorded
Fixed release recorded from official guidance
ENISA EUVD · EUVD-2026-73308↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-78510 · cve.blacktree.nl