VulnerabilityAnalyzed
CVE-2026-50517
Deserialization of untrusted data in M365 Copilot allows an authorized attacker to execute code over a network.
CRITICAL 9.9EPSS 1.25%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.25%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Deserialization of untrusted data in M365 Copilot allows an authorized attacker to execute code over a network.
- CVSS 3.1
- 9.9 CRITICALCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- EPSS
- 1.25% probability · 68th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-502
- Affected
- microsoft/365 copilot
- Source
- secure@microsoft.com
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.