Vulnerability Description
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.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Freerdp | Freerdp | < 3.26.0 |
Related Weaknesses (CWE)
References
- https://github.com/FreeRDP/FreeRDP/commit/d7508ebcd82842a691ae4941e5104d14240a89
- https://github.com/FreeRDP/FreeRDP/pull/12713
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-p6r2-4hgm-m6ffExploitMitigationVendor Advisory
- https://www.vulncheck.com/advisories/freerdp-heap-buffer-overflow-in-gdi-cachetoThird Party Advisory
- https://access.redhat.com/errata/RHSA-2026:36203
- https://access.redhat.com/errata/RHSA-2026:46393
- https://access.redhat.com/security/cve/CVE-2026-40033
- https://bugzilla.redhat.com/show_bug.cgi?id=2481473
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-p6r2-4hgm-m6ffExploitMitigationVendor Advisory
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40033.json
FAQ
What is CVE-2026-40033?
CVE-2026-40033 is a vulnerability with a CVSS score of 8.8 (HIGH). 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 va...
How severe is CVE-2026-40033?
CVE-2026-40033 has been rated HIGH with a CVSS base score of 8.8/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-40033?
Check the references section above for vendor advisories and patch information. Affected products include: Freerdp Freerdp.