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.

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.

Published 2026-01-22 · last modified 2026-06-17.

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.

EPSS exploit prediction

EPSS: 0.009 (59.2th percentile), scored 2026-10-19.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 59th percentile — 59.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: -0.000

Affected products

Weakness classification (CWE)

CWE-1287

References

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

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.