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CVE-2026-65801: Microsoft Exchange Online Elevation of Privilege Vulnerability

criticalCVSS 10CVE-2026-65801
Server-side request forgery (ssrf) in Microsoft Exchange Online allows an unauthorized attacker to elevate privileges over a network.

CSIRTS triage

vendor: Microsoftproduct: Exchange OnlineServer-side request forgeryPrivilege escalation
What
Server-side request forgery allows an attacker to elevate privileges.
Who is affected
All Exchange Online deployments are potentially affected.
Urgency
Critical severity and CVSS 10 score warrant immediate patching despite no active exploitation reported.
Action
Apply available security updates from Microsoft immediately.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source
Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity
critical — CVSS 10
Published
2026-08-11
Exploitation
Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-65801

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Referenced CVEs

CVECSIRTS overviewExternal
CVE-2026-65801coverage & exploitation statusNVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

Recent advisories for Microsoft Exchange Online

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

More from Microsoft Security Response Center