CVE-2026-91948 FreeRDP before 3.31.0 Out-of-bounds Write via SHOW_PROTOCOL
Authenticated clients can trigger heap corruption in FreeRDP server-side channel handling, potentially leading to remote code execution.
- 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-2026-91948?
CVE-2026-91948 is a high-severity memory corruption vulnerability in FreeRDP, published on 15 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
FreeRDP versions before 3.31.0 contain an out-of-bounds write vulnerability in server-side static virtual channel handling when CHANNEL_OPTION_SHOW_PROTOCOL is enabled. Authenticated clients can queue oversized channel messages that cause buffer underflow and corrupt heap memory including live pointers, potentially enabling code execution.
Weakness: CWE-191
Which versions are affected by CVE-2026-91948?
How do I fix CVE-2026-91948?
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-2026-91948 being exploited?
There is no known exploitation of CVE-2026-91948 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-91948, GHSA-9jcm-x588-gh26, GHSA-vg28-cmpq-3hp8, UBUNTU-CVE-2026-91948.