What is CVE-2026-65801?

CVE-2026-65801 is a critical-severity vulnerability in Microsoft Exchange Online, classified under Server-Side Request Forgery (SSRF). CVSS score: 10.0/10. Published 2026-08-20.

How severe is CVE-2026-65801?

Critical severity. CVSS v3 base score is 10.0 out of 10.

SSRF in Microsoft Exchange Online

CVE-2026-65801

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

Vulnerability class: SSRF (Server-Side Request Forgery)

CVSS v3 metric

CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

Affected products

Microsoft Exchange Online

Weakness classification (CWE)

CWE-918 — Server-Side Request Forgery (SSRF)

References

secure@microsoft.com (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-65801?: CVE-2026-65801 is a critical-severity vulnerability in Microsoft Exchange Online, classified under Server-Side Request Forgery (SSRF). CVSS score: 10.0/10. Published 2026-08-20.
How severe is CVE-2026-65801?: Critical severity. CVSS v3 base score is 10.0 out of 10.