Vulnerability in Microsoft 365 Copilot

CVE-2026-24307

Improper validation of specified type of input in M365 Copilot allows an unauthorized attacker to disclose information over a network.

EPSS: 0.002 (41.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.3 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N/E:U/RL:O/RC:C.

Affected products

Microsoft 365 Copilot

Weakness classification (CWE)

CWE-1287

References

M365 Copilot Information Disclosure Vulnerability (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-24307?: CVE-2026-24307 is a critical-severity vulnerability in Microsoft 365 Copilot, classified under CWE-1287. CVSS score: 9.3/10. Published 2026-01-22.
How severe is CVE-2026-24307?: Critical severity. CVSS v3 base score is 9.3 out of 10.