Critical Buffer Overflow Vulnerability in FreeRDP Disclosed

• •CVE-2026-91959 affects FreeRDP versions before 3.31.0.
• •Attackers can exploit this vulnerability to crash FreeRDP clients via malicious BIND_ACK PDUs.
• •Immediate updates are recommended to mitigate the denial-of-service risk.

CVE-2026-91959 is a buffer over-read vulnerability affecting FreeRDP versions prior to 3.31.0, allowing attackers to crash clients via malicious BIND_ACK PDUs. This flaw impacts users connecting through the Remote Desktop Gateway, creating a denial-of-service condition. Exploitation requires user interaction to connect to a compromised gateway. The vulnerability was published on September 15, 2026, and affects applications embedding FreeRDP for RDP connectivity. The issue arises from insufficient validation in the rts_read_result function, leading to out-of-bounds reads. Security advisories recommend immediate updates to mitigate risks. The vulnerability has been confirmed to cause crashes in default builds of FreeRDP.