CVE-2026-109246 FreeRDP before 3.32.0 Shadow Server Divide-by-Zero via Frame Acknowledge PDU
An authenticated client can cause a divide-by-zero crash in the FreeRDP shadow server, disconnecting all viewers.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-109246?
CVE-2026-109246 is a high-severity vulnerability in FreeRDP, published on 12 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
FreeRDP before 3.32.0 contains a divide-by-zero vulnerability in the freerdp-shadow-cli shadow server: the frame id in a client's Frame Acknowledge PDU is stored without a range check, so the in-flight frame count in shadow_encoder_inflight_frames() can underflow. An authenticated client can acknowledge a frame id one greater than the last frame sent, causing shadow_encoder_create_frame_id() to divide by zero (SIGFPE) and terminate the process, disconnecting all viewers.
Weakness: CWE-191
Which versions are affected by CVE-2026-109246?
How do I fix CVE-2026-109246?
Upgrade to a fixed version.
Is CVE-2026-109246 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-109246 exists.
Sources
Also known as DEBIAN-CVE-2026-109246, GHSA-6vjv-4hm3-6698, GHSA-jpmc-9q62-wvpv, UBUNTU-CVE-2026-109246.