by Kastro
Paper/Archive/CVE-2026-50517

CVE-2026-50517

Microsoft Microsoft 365 Copilot — Microsoft M365 Copilot Remote Code Execution Vulnerability

EPSS 2%CVSS 9.9
critical.is priorityof 100
45
CVSS 9.9 (CNA)9.9 / 10 × 3029.7Not in CISA KEV+300.0EPSS percentile 77.1.771 × 2015.4No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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

Affected

ProductAffectedFixed inSource
Microsoft 365 Copilot-–CNA

Scores by source

microsoft (CNA)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
CISA ADPSSVCExploitation: none · Automatable: no · Technical impact: total

References

patchmsrc.microsoft.com/update-guide/vulnerability/CVE-2026-50517