Buffer overflow in Microsoft 365_copilot

CVE-2025-53766

Heap-based buffer overflow in Windows GDI+ allows an unauthorized attacker to execute code over a network.

Vulnerability class: Buffer Overflow

EPSS: 0.028 (86.4th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-53766?
CVE-2025-53766 is a critical-severity vulnerability in Microsoft 365_copilot, classified under Heap-based Buffer Overflow. CVSS score: 9.8/10. Published 2025-08-12.
How severe is CVE-2025-53766?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2025-53766 known to be exploited?
5 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.