What’s Vulnerable › Vulnerabilities

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

• Severity: critical (CVSS 9.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-24 · updated 2026-10-28
• Weakness: CWE-502

Description

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

Affected products

• Microsoft 365 Copilot: all versions
• Microsoft 365 Copilot: all versions

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50517

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