CVE-2026-91951 FreeRDP 3.14.0 through 3.30.0 Out-of-bounds Write via urbdrc
A malicious RDP server can cause a denial of service in FreeRDP clients via an out-of-bounds write in the USB redirection channel when verbose asserts are enabled.
- 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-2026-91951?
CVE-2026-91951 is a high-severity memory corruption vulnerability in Freerdp Freerdp, published on 15 Sep 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 versions before 3.31.0 contain an out-of-bounds write vulnerability in the urbdrc client channel's urb_send_current_frame_number_result() function. A malicious RDP server can send a crafted 28-byte USB redirection message to trigger a 4-byte write past the allocated 16-byte buffer, causing denial of service when verbose asserts are enabled.
Weakness: CWE-617
Which versions are affected by CVE-2026-91951?
It affects 1 product.
Products include Freerdp Freerdp.
How do I fix CVE-2026-91951?
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-2026-91951 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-91951 exists.
Other vulnerabilities in Freerdp Freerdp
- CVE-2021-37594 Other in n/a
- CVE-2021-37595 Other in n/a
- CVE-2026-67305 FreeRDP Windows Client before 3.29.0 Heap Buffer Overflow via Cliprdr
- CVE-2026-66402 FreeRDP before 3.29.0 TLS Certificate Identity Validation Bypass
- CVE-2026-67289 FreeRDP before 3.29.0 HTTP Proxy Request Injection via Redirection
Sources
Also known as DEBIAN-CVE-2026-91951, GHSA-8rv4-fc8j-9xvc, GHSA-h5w2-q35j-443h, UBUNTU-CVE-2026-91951.