Buffer overflow in Freerdp
CVE-2026-40033
FreeRDP before 3.26.0 contains a heap-buffer-overflow vulnerability in gdi_CacheToSurface that allows remote attackers to write out-of-bounds heap memory. The vulnerability occurs because rectangle validation clamps coordinates to UINT16_MAX but performs copy operations using unclamped cache entry dimensions, enabling malicious RDP servers to trigger large out-of-bounds writes and potentially achieve remote code execution or client crash.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.011 (63.2th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 63rd percentile — 63.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.010 · newest: 0.011 · change: +0.000
Affected products
- Freerdp — versions 0, 3.26.0
Weakness classification (CWE)
References
- github.com/FreeRDP/FreeRDP/security/advisories/GHSA-p6r2-4hgm-m6ff (Exploit, vendor-advisory, Mitigation, Vendor Advisory)
- github.com/FreeRDP/FreeRDP/commit/23b36cd00ebf0ccd97750fcdbc9aa2f362352da7 (Patch, patch)
- www.vulncheck.com/advisories/freerdp-heap-buffer-overflow-in-gdi-cachetosurface… (Third Party Advisory, third-party-advisory)
- github.com/FreeRDP/FreeRDP/pull/12713 (issue-tracking)
- github.com/FreeRDP/FreeRDP/commit/d7508ebcd82842a691ae4941e5104d14240a89ae (patch)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Frequently asked questions
- What is CVE-2026-40033?
- CVE-2026-40033 is a high-severity vulnerability in Freerdp, classified under Heap-based Buffer Overflow. CVSS score: 8.8/10. Published 2026-05-26.
- How severe is CVE-2026-40033?
- High severity. CVSS v3 base score is 8.8 out of 10.