BlackTreeCVE Intelligence
← Back to the CVE catalogue
Full vulnerability report · 2026
CVE-2026-55007High confidence

Microsoft Exchange Server Remote Code Execution Vulnerability

Microsoft · Microsoft Exchange Server 2019 Cumulative Update 14

8.1HighCVSS 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-2026-73178

No EUVD known-exploited evidence

Double free in Microsoft Exchange Server allows an unauthorized attacker to execute code over a network.

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
8.1 · 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

Double free in Microsoft Exchange Server allows an unauthorized attacker to execute code over a network.

What

Double free in Microsoft Exchange Server allows an unauthorized attacker to execute code over a network.

Why

The product calls free() twice on the same memory address.

How

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

What

Double free in Microsoft Exchange Server allows an unauthorized attacker to execute code over a network.

Why

The product calls free() twice on the same memory address.

How

An attacker operating through a network path 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
a network path → Double Free → execute code or commands in the affected security context
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
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-415 ↗

CWE-415: Double Free. The product calls free() twice on the same memory address.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:H/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.

AVNetworkAttack vector: The vulnerable component can be reached over a network.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.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.
NetworkUnauthenticatedRemote code executionCWE-415
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-73178Official EUVD mapping

Double free in Microsoft Exchange Server allows an unauthorized attacker to execute code over a network.

Official EUVD record ↗
BSI · German · WID-SEC-2026-3243Microsoft Windows: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in verschiedenen Versionen von Microsoft Windows Server, Microsoft Windows 10 und Microsoft Windows 11 ausnutzen, um seine Privilegien zu erhöhen, um einen Denial of Service herbeizuführen, um Informationen offenzulegen und um beliebigen Code auszuführen.

Official advisory ↗
BSI · German · WID-SEC-2026-3268Microsoft Exchange Server: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Microsoft Exchange Server ausnutzen, um beliebigen Code auszuführen, Spoofing-Angriffe durchzuführen, erweiterte Berechtigungen zu erlangen, Daten zu manipulieren oder offenzulegen sowie einen Denial-of-Service-Angriff zu verursachen.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-1149Multiples vulnérabilités dans les produits Microsoft

de compromission Flux RSS des durcissement et recommandations Flux RSS des bulletins d'actualité Premier Ministre S.G.D.S.N Agence nationale de la sécurité des systèmes d'information Paris, le 09 septembre 2026 N° CERTFR-2026-AVI-1149 Affaire suivie par: CERT-FR Avis du CERT-FR Objet: Multiples vulnérabilités dans les produits Microsoft Gestion du document Référence CERTFR-2026-AVI-1149 Titre Multiples vulnérabilités dans les produits Microsoft Date de la première version 09 septembre 2026 Date de la dernière version 09 septembre 2026 Source(s) Bulletin de sécurité Microsoft CVE-2026-47297 du 08 septembre 2026 Bulletin de sécurité Microsoft CVE-2026-55007 du 08 septembre 2026 Bulletin de sécurité Microsoft CVE-2026-57099 du 08 septembre 2026 Bulletin de sécurité Microsoft CVE-2026-58599 du 08 septembre 2026 Bulletin de sécurité Microsoft CVE-2026-58600 du 08 septembre 2026 Bulletin de sécurité Microsoft CVE-2026-58611 du 08 septembre 2026 Bulletin de sécurité Microsoft CVE-2026-58649 du 08 septembre 2026 Bulletin de sécurité Microsoft CVE-2026-63523 du 08 septembre 2026 Bulletin de sécurité Microsoft CVE-2026-65669 du 08 septembre 2026 Bulletin de sécurité Microsoft CVE-2026-65772 du 08 septembre 2026 Bulletin de sécurité Microsoft CVE-2026-65812 du 08 septembre 2026 Bulletin de sécurité Micr

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

Windows Win32K Windows Wireless Networking Windows Wireless Wide Area Network Service Windows Work Folder Service Windows Work Folders Windows exFAT File System Windows iSCSI Windows iSCSI Target Service Winsock XBox Gaming Services Xbox Azioni di mitigazione In linea con le dichiarazioni del vendor, si raccomanda di procedere all’aggiornamento dei prodotti impattati attraverso l’apposita funzione di Windows Update. CVE (973) Cerca: Tabella CVE CVE POC EXPLOITATION CVE-2026-58649 : apre una nuova finestra - - CVE-2026-62906 : apre una nuova finestra - - CVE-2026-66820 : apre una nuova finestra - - CVE-2026-66819 : apre una nuova finestra - - CVE-2026-55007 : apre una nuova finestra - - CVE-2026-62694 : apre una nuova finestra - - CVE-2026-66814 : apre una nuova finestra - - CVE-2026-66816 : apre una nuova finestra - - CVE-2026-66818 : apre una nuova finestra - - CVE-2026-62697 : apre una nuova finestra - - CVE-2026-67381 : apre una nuova finestra - - CVE-2026-67380 : apre una nuova finestra - - CVE-2026-67383 : apre una nuova finestra - - CVE-2026-69321 : apre una nuova finestra - - CVE-2026-67385 : apre una nuova finestra - - CVE-2026-62804 : apre una nuova finestra - - CVE-2026-67384 : apre una nuova finestra - - CVE-2026-69319 : apre una nuova finestra - - CVE-2026-67376 : apre una nuova fi

Official advisory ↗
NCSC-NL · Dutch · NCSC-2026-0349Kwetsbaarheden verholpen in Microsoft Exchange server

Een kwaadwillende kan de kwetsbaarheden misbruiken om een Denial-of-Service uit te voeren, zich voor te doen als andere gebruiker, zich verhoogde rechten toe te kennen, willekeurige code uit te voeren en/of toegang te krijgen tot gevoelige gegevens. De ernstigste kwetsbaarheid met kenmerk CVE-2026-69380 heeft een CVSS-score van 9,9 en betreft een autorisatiekwetsbaarheid. Een geauthenticeerde kwaadwillende met beperkte rechten en een toegewezen mailbox kan via het netwerk zijn rechten verhogen en zich voordoen als andere gebruikers. Hierdoor kan de kwaadwillende mailboxen van Exchange-gebruikers overnemen, e-mails lezen en verzenden en bijlagen downloaden. De kwetsbaarheid met kenmerk CVE-2026-69356 heeft een CVSS-score van 9,3 en betreft een XSS-kwetsbaarheid. Een ongeauthenticeerde kwaadwillende kan een speciaal geprepareerde agenda-uitnodiging versturen. Als een gebruiker de vergaderlink opent, kan de kwaadwillende scripts uitvoeren binnen de Outlook on the Web-sessie en mailboxgegevens inzien of wijzigen. De kwetsbaarheid met kenmerk CVE-2026-69641 heeft een CVSS-score van 9,1 en betreft een autorisatiekwetsbaarheid. Een geauthenticeerde kwaadwillende met zeer hoge rechten kan via een speciaal geprepareerd verzoek mailboxautorisatiecontroles omzeilen en toegang krijgen tot de mailbox van andere gebruikers. Hierdoor kan de kwaadwillende mailboxen overnemen, e-mails lezen en verzenden en bijlagen downloaden. ``` Microsoft Exchange Server: |----------------|------|-------------------------------------| | CVE-ID | CVSS | Impact | |----------------|------|-------------------------------------| | CVE-2026-55007 | 8,10 | Uitvoeren van willekeurige code | | CVE-2026-69355 | 8,80 | Uitvoeren van willekeurige code | | CVE-2026-69356 | 9,30 | Voordoen als andere gebruiker | | CVE-2026-69361 | 6,50 | Voordoen als andere gebruiker | | CVE-2026-69375 | 6,50 | Tampering | | CVE-2026-69378 | 7,50 | Denial-of-Service | | CVE-2026-69380 | 9,90 | Verkrijgen van verhoogde rechten | | CVE-2026-69382 | 5,90 | Toegang tot gevoelige gegevens | | CVE-2026-69641 | 9,10 | 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. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 8 Sept 2026 · Last source change 11 Sept 2026, 22:09 UTC · CWE-415 · Double Free

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-2026-73178
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceOther authority
NVD statusNVD awaiting 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
    15.02.0.0 < 15.02.1544.046; 15.02.0.0 < 15.02.1748.051; 15.02.0.0 < 15.02.2562.049 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    Microsoft Exchange Server 2019 Cumulative Update 14: 15.02.0.0 < 15.02.1544.046; Microsoft Exchange Server 2019 Cumulative Update 15: 15.02.0.0 < 15.02.1748.051; Microsoft Exchange Server Subscription Edition RTM: 15.02.0.0 < 15.02.2562.049 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
  2. ENISA EUVD mappingEUVD-2026-73178 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-73178"}
    ENISA EUVD ↗
  3. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2026-73178↗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-2026-55007 · cve.blacktree.nl