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
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.082 (94.9th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 95th percentile — 94.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.080 · newest: 0.082 · change: +0.002
Affected products
- Microsoft 365 Copilot
- Microsoft Office For Android — versions 16.0.1
- Microsoft Office For Universal — versions 16.0.1
- Microsoft Office
- Microsoft Windows 10 1507
- Microsoft Windows 10 1607
- Microsoft Windows 10 1809
- Microsoft Windows 10 21h2
- Microsoft Windows 10 22h2
- Microsoft Windows 10 Version 1507 — versions 10.0.10240.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- msrc.microsoft.com/update-guide/vulnerability/CVE-2025-53766 (vendor-advisory, patch, Vendor Advisory)
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.