CVE-2026-50517 CRITICAL

CVE-2026-50517: Microsoft M365 Copilot Remote Code Execution Vulnerability

Vendor Microsoft

Product Microsoft 365 Copilot

Weakness CWE-502 · Unsafe deserialization

Published July 24, 2026

Last update July 24, 2026

View on NVD All CVEs

CVSS base score

9.9/10

Attack vector Network

Attack complexity Low

Privileges required Low

User interaction None

Confidentiality High

Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C

What the vulnerability does

01Description

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

Key dates

02Disclosure timeline

July 24, 2026 CVE published

July 24, 2026 Record updated

External resources

03References

NVD — National Vulnerability Database https://nvd.nist.gov/vuln/detail/CVE-2026-50517 CWE — Common Weakness Enumeration https://cwe.mitre.org/data/definitions/502.html AskarLabs — CWE-502 write-up Deserialization of Untrusted Data

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