CVE-2026-109251 FreeRDP before 3.32.0 Out-of-Bounds Write via MS-RDPEGT Video Geometry
A malicious RDP server can trigger an out-of-bounds write in FreeRDP clients using video features, potentially leading to code execution or crashes.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-109251?
CVE-2026-109251 is a medium-severity memory corruption vulnerability in FreeRDP, published on 12 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
FreeRDP before 3.32.0 stores the server-supplied signed MS-RDPEGT geometry origin unchecked in an unsigned video surface coordinate, so the blit clamp in gdiVideoShowSurface() wraps in 32-bit arithmetic and is skipped. A malicious RDP server can send a negative topLevelLeft to clients connecting with /video, causing an out-of-bounds write of decoded H.264 picture data or a client abort.
Weakness: CWE-129
Which versions are affected by CVE-2026-109251?
How do I fix CVE-2026-109251?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-109251 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-109251 exists.
Sources
Also known as DEBIAN-CVE-2026-109251, GHSA-grvc-qhhp-7h6m, GHSA-wv34-x2ff-j6qm, UBUNTU-CVE-2026-109251.