59/59 sources · synced 00:50 UTC Customize Public mode
CVE-2026-50517Critical

Microsoft M365 Copilot Remote Code Execution Vulnerability

MSRC advisory NVD CVE.org

Assessment

Deserialization of untrusted data in M365 Copilot allows an authorized attacker to execute code over a network.

Severity
Critical
CVSS base score
9.9CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C
Impact
Remote Code Execution
EPSS, next 30 days
1.7%Higher than 76.2% of scored CVEs · FIRST model run 26 Sep 2026 · about EPSS
Exploitability
Not assessed
Publicly disclosed
No
Customer action
Not required (service-side fix)
Component
M365 Copilot
Weakness
CWE-502: Deserialization of Untrusted Data
Issued by
Microsoft
Published
23 Jul 2026 · July 2026
Last revised
23 Jul 2026

Updates that fix it

0 KBs

No KB listed

MSRC lists no downloadable update, which usually means a service-side fix or a release-notes update. Check the MSRC advisory.

Affected products

Apps
1 affected product
  • Microsoft 365 Copilot
ChangeIntel is an independent tool and is not affiliated with or endorsed by Microsoft. Microsoft, Windows, Microsoft 365, Azure, and related names are trademarks of the Microsoft group of companies. Data comes from public sources listed on Sources; every item links to its original page. Dates and statuses can change after they are read. Built by Evotec. This is the public demo. It can also run on your own server, with your Microsoft 365 tenant and device data kept inside your network; Evotec can help you deploy and extend it.