CVE-2026-26137

CRITICAL

Microsoft 365 Copilot BizChat Elevation of Privilege Vulnerability

Title source: cna
STIX 2.1

Description

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

References (1)

Core 1
Core References
Vendor Advisory vendor-advisory patch
Microsoft 365 Copilot BizChat Elevation of Privilege Vulnerability
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26137

Scores

CVSS v3 9.9
EPSS 0.0054
EPSS Percentile 40.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact total

Details

CWE
CWE-918
Status published
Products (3)
microsoft/365_copilot_chat
Microsoft/Microsoft 365 Copilot's Business Chat -
Microsoft/Microsoft Exchange Online -
Published Mar 19, 2026
Tracked Since Mar 20, 2026