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Full vulnerability report · 2026
CVE-2026-44818High confidence

Microsoft Excel Remote Code Execution Vulnerability

Microsoft · Microsoft 365 Apps for Enterprise

7.0HighCVSS 3.1
Recommended action
Within 7 days

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

Patch available
Optional official sources

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

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

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-2026-35661

No EUVD known-exploited evidence

Concurrent execution using shared resource with improper synchronization ('race condition') in Microsoft Office Excel 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
7.0 · 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

Concurrent execution using shared resource with improper synchronization ('race condition') in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

What

Concurrent execution using shared resource with improper synchronization ('race condition') in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

Why

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

How

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

What

Concurrent execution using shared resource with improper synchronization ('race condition') in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

Why

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

How

An attacker operating through local access may attempt exploitation without authentication after a 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 → Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') → execute code or commands in the affected security context
Attack surface
Local
Privileges required
None: unauthenticated exploitation is possible
User interaction
Required interaction required
Attack complexity
High: exploitation depends on specific conditions
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-362 ↗

CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition'). The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

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:H/PR:N/UI:R/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.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.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-362
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-35661Official EUVD mapping

Concurrent execution using shared resource with improper synchronization ('race condition') in Microsoft Office Excel allows an unauthorized attacker to execute code locally.

Official EUVD record ↗
BSI · German · WID-SEC-2026-1847Microsoft Office: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in verschiedenen Microsoft Office und SharePoint Produkten ausnutzen, um Administratorrechte zu erlangen, beliebigen Code auszuführen, Spoofing-Angriffe durchzuführen, Daten zu manipulieren oder vertrauliche Informationen offenzulegen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260610Security Bulletin 10 Jun 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 10 Jun 2026, published on 10 June 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0727Multiples vulnérabilités dans Microsoft Office

.S.N Agence nationale de la sécurité des systèmes d'information Paris, le 10 juin 2026 N° CERTFR-2026-AVI-0727 Affaire suivie par: CERT-FR Avis du CERT-FR Objet: Multiples vulnérabilités dans Microsoft Office Gestion du document Référence CERTFR-2026-AVI-0727 Titre Multiples vulnérabilités dans Microsoft Office Date de la première version 10 juin 2026 Date de la dernière version 10 juin 2026 Source(s) Bulletin de sécurité Microsoft Office CVE-2026-44803 du 09 juin 2026 Bulletin de sécurité Microsoft Office CVE-2026-44812 du 09 juin 2026 Bulletin de sécurité Microsoft Office CVE-2026-44817 du 09 juin 2026 Bulletin de sécurité Microsoft Office CVE-2026-44818 du 09 juin 2026 Bulletin de sécurité Microsoft Office CVE-2026-44819 du 09 juin 2026 Bulletin de sécurité Microsoft Office CVE-2026-44820 du 09 juin 2026 Bulletin de sécurité Microsoft Office CVE-2026-44821 du 09 juin 2026 Bulletin de sécurité Microsoft Office CVE-2026-44822 du 09 juin 2026 Bulletin de sécurité Microsoft Office CVE-2026-44823 du 09 juin 2026 Bulletin de sécurité Microsoft Office CVE-2026-44824 du 09 juin 2026 Bulletin de sécurité Microsoft Office CVE-2026-45455 du 09 juin 2026 Bulletin de sécurité Microsoft Office CVE-2026-45456 du 09 juin 2026 Bulletin de sécurité Microsoft Office CVE-2026-45457 du 09 juin 2026 Bulletin de

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-019416マイクロソフトのMicrosoft 365 Apps等の複数製品における競合状態に関する脆弱性

Microsoft Office Excel における整数のアンダーフロー（ラップアラウンド）により、権限のない攻撃者がローカルでコードを実行する可能性があります。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6837MS 6월 보안 위협에 따른 정기 보안 업데이트 권고

| Windows DWM 핵심 라이브러리 | CVE-2026-44811 | Windows DWM Core Library Elevation of Privilege Vulnerability | | Windows Win32K - GRFX | CVE-2026-44812 | Windows Graphics Component Remote Code Execution Vulnerability | | Windows DWM 핵심 라이브러리 | CVE-2026-44813 | Windows DWM Core Library Elevation of Privilege Vulnerability | | Windows DWM 핵심 라이브러리 | CVE-2026-44814 | Windows DWM Core Library Information Disclosure Vulnerability | | Windows DHCP 클라이언트 | CVE-2026-44815 | DHCP Client Service Remote Code Execution Vulnerability | | Microsoft Office Excel | CVE-2026-44817 | Microsoft Excel Remote Code Execution Vulnerability | | Microsoft Office Excel | CVE-2026-44818 | Microsoft Excel Remote Code Execution Vulnerability | | Microsoft Office Word | CVE-2026-44819 | Microsoft Office Remote Code Execution Vulnerability | | Microsoft Office Excel | CVE-2026-44820 | Microsoft Excel Remote Code Execution Vulnerability | | Microsoft Office Word | CVE-2026-44821 | Microsoft Office Information Disclosure Vulnerability | | Microsoft Office Excel | CVE-2026-44822 | Microsoft Excel Information Disclosure Vulnerability | | Microsoft Office Excel | CVE-2026-44823 | Microsoft Excel Remote Code Execution Vulnerability | | Microsoft Office Word | CVE-2026-44824 | Microsoft Office Remote Code Execution Vulnerability | | M

Official advisory ↗
NCSC-NL · Dutch · NCSC-2026-0182Kwetsbaarheden verholpen in Microsoft Office

Een kwaadwillende kan de kwetsbaarheden misbruiken om aanvallen uit te voeren die kunnen leiden tot de categorieën schade, zoals omschreven in onderstaande tabellen. Voor succesvol misbruik moet de kwaadwillende het slachtoffer misleiden een malafide bestand te openen of link te volgen. ``` Microsoft Office SharePoint: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-45467 | 4.60 | Voordoen als andere gebruiker | | CVE-2026-45468 | 4.60 | Voordoen als andere gebruiker | | CVE-2026-45479 | 4.60 | Voordoen als andere gebruiker | | CVE-2026-45453 | 5.40 | Voordoen als andere gebruiker | | CVE-2026-47298 | 8.00 | Uitvoeren van willekeurige code | | CVE-2026-47636 | 5.40 | Voordoen als andere gebruiker | | CVE-2026-47637 | 4.60 | Voordoen als andere gebruiker | | CVE-2026-47638 | 4.60 | Voordoen als andere gebruiker | | CVE-2026-47639 | 5.40 | Voordoen als andere gebruiker | | CVE-2026-47641 | 4.60 | Voordoen als andere gebruiker | | CVE-2026-33113 | 5.40 | Voordoen als andere gebruiker | | CVE-2026-45454 | 6.50 | Uitvoeren van willekeurige code | | CVE-2026-45462 | 4.60 | Voordoen als andere gebruiker | | CVE-2026-45464 | 5.40 | Voordoen als andere gebruiker | | CVE-2026-45465 | 5.40 | Voordoen als andere gebruiker | | CVE-2026-47634 | 7.30 | Voordoen als andere gebruiker | | CVE-2026-47640 | 4.60 | Voordoen als andere gebruiker | | CVE-2026-45481 | 7.30 | Voordoen als andere gebruiker | | CVE-2026-45484 | 8.80 | Verkrijgen van verhoogde rechten | | CVE-2026-48560 | 5.40 | Voordoen als andere gebruiker | | CVE-2026-48562 | 4.60 | Voordoen als andere gebruiker | |----------------|------|-------------------------------------| Windows Win32K - GRFX: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-44803 | 7.80 | Uitvoeren van willekeurige code | | CVE-2026-44812 | 7.80 | Uitvoeren van willekeurige code | |----------------|------|-------------------------------------| Microsoft Office Word: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-45475 | 7.80 | Uitvoeren van willekeurige code | | CVE-2026-45471 | 7.80 | Uitvoeren van willekeurige code | | CVE-2026-45486 | 7.80 | Uitvoeren van willekeurige code | | CVE-2026-45485 | 3.30 | Toegang tot gevoelige gegevens | | CVE-2026-44819 | 7.80 | Uitvoeren van willekeurige code | | CVE-2026-44821 | 5.50 | Toegang tot gevoelige gegevens | | CVE-2026-44824 | 7.80 | Uitvoeren van willekeurige code | | CVE-2026-45466 | 3.30 | Toegang tot gevoelige gegevens | | CVE-2026-45643 | 7.80 | Uitvoeren van willekeurige code | | CVE-2026-45457 | 7.80 | Uitvoeren van willekeurige code | |----------------|------|-------------------------------------| Microsoft Teams for Android: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-42835 | 8.10 | Toegang tot gevoelige gegevens | |----------------|------|-------------------------------------| Office for Android: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-45649 | 7.10 | Voordoen als andere gebruiker | |----------------|------|-------------------------------------| Microsoft Office Project: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-45483 | 4.60 | Voordoen als andere gebruiker | |----------------|------|-------------------------------------| Microsoft Office: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-45472 | 8.40 | Uitvoeren van willekeurige code | | CVE-2026-45474 | 8.40 | Uitvoeren van willekeurige code | | CVE-2026-45456 | 8.40 | Uitvoeren van willekeurige code | | CVE-2026-45458 | 8.40 | Uitvoeren van willekeurige code | | CVE-2026-45460 | 4.70 | Toegang tot gevoelige gegevens | | CVE-2026-45461 | 8.40 | Uitvoeren van willekeurige code | | CVE-2026-45645 | 7.80 | Uitvoeren van willekeurige code | | CVE-2026-47635 | 8.40 | Uitvoeren van willekeurige code | | CVE-2026-45463 | 8.40 | Uitvoeren van willekeurige code | |----------------|------|-------------------------------------| Microsoft Office Excel: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-45469 | 7.80 | Uitvoeren van willekeurige code | | CVE-2026-44817 | 7.80 | Uitvoeren van willekeurige code | | CVE-2026-44818 | 7.00 | Uitvoeren van willekeurige code | | CVE-2026-44820 | 7.80 | Uitvoeren van willekeurige code | | CVE-2026-44823 | 7.80 | Uitvoeren van willekeurige code | | CVE-2026-44822 | 8.20 | Toegang tot gevoelige gegevens | | CVE-2026-45455 | 3.30 | Toegang tot gevoelige gegevens | | CVE-2026-45459 | 3.30 | Omzeilen van beveiligingsmaatregel | |----------------|------|-------------------------------------| Microsoft Office Click-To-Run: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-47293 | 7.00 | Verkrijgen van verhoogde rechten | |----------------|------|-------------------------------------| ```

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
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.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 9 Jun 2026 · Last source change 25 Aug 2026, 22:43 UTC · CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

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 2026-08-14
European sourceENISA EUVD · EUVD-2026-35661
Product sourceCNA
Remediation sourceCVE/CNA references
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 ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2026-35661↗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-2026-44818 · cve.blacktree.nl