CVE-2026-40033
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Mitigation details
CVE-2026-40033 NameCVE-2026-40033 DescriptionFreeRDP 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…
CVE-2026-40033
| Name | CVE-2026-40033 |
| 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. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| freerdp2 (PTS) | bullseye | 2.3.0+dfsg1-2+deb11u1 | vulnerable |
| bullseye (security) | 2.3.0+dfsg1-2+deb11u3 | vulnerable | |
| bookworm | 2.11.7+dfsg1-6~deb12u1 | vulnerable | |
| freerdp3 (PTS) | trixie | 3.15.0+dfsg-2.1+deb13u3 | vulnerable |
| forky, sid | 3.26.0+dfsg-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| freerdp2 | source | (unstable) | (unfixed) | |||
| freerdp3 | source | (unstable) | 3.26.0+dfsg-1 |
Notes
[trixie] - freerdp3 <no-dsa> (Minor issue)
[bookworm] - freerdp2 <no-dsa> (Minor issue)
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-p6r2-4hgm-m6ff
unclear fixing commit references, incorrect reference in CVE entry?
Apply commands
[trixie] - freerdp3 <no-dsa> (Minor issue)[bookworm] - freerdp2 <no-dsa> (Minor issue)https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-p6r2-4hgm-m6ffunclear fixing commit references, incorrect reference in CVE entry?OS impact
SUSE Affected 1 release
| Version | Status | Fixed in |
|---|---|---|
| — | Affected | — |
Debian Mixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Affected | — |
| sid | Fixed | 3.26.0+dfsg-1 |
| forky | Fixed | 3.26.0+dfsg-1 |
| bullseye | Affected | — |
| bookworm | Affected | — |
Application impact
| Vendor | Product | Versions | Fixed |
|---|---|---|---|
| freerdp | freerdp | {"endExcluding":"3.26.0"} | 3.26.0 |
References
- https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-p6r2-4hgm-m6ff
- https://github.com/FreeRDP/FreeRDP/commit/23b36cd00ebf0ccd97750fcdbc9aa2f362352da7
- https://www.vulncheck.com/advisories/freerdp-heap-buffer-overflow-in-gdi-cachetosurface-via-rectangle-validation-bypass
- https://www.suse.com/security/cve/CVE-2026-40033.html
- https://security-tracker.debian.org/tracker/CVE-2026-40033
CWEs
CWE-122
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.