CVE-2026-55193
HighCVSS 8.7Summary
In FreeRDP before 3.27.0, clients using TS Gateway accept a server-controlled max_xmit_frag value without bounding it to the ReceiveFragment allocation. A malicious gateway can advertise 65535 and send a response fragment of that length, causing a buffer overflow in the ReceiveFragment buffer. This can crash the client and may permit code execution.
Risk Assessment
A malicious TS Gateway can crash the client or achieve code execution, posing a serious security threat.
Recommendation
Update FreeRDP to version 3.27.0 or later, which includes the fix.
Original NVD description (English source)
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, FreeRDP clients using TS Gateway accept a server-controlled max_xmit_frag value in libfreerdp/core/gateway/rpc_bind.c without bounding it to the 4088-byte ReceiveFragment allocation. A malicious gateway can advertise 65535 and then send a response fragment of the same length, causing rpc_channel_read in libfreerdp/core/gateway/rpc.c to write up to 65535 bytes into the smaller ReceiveFragment buffer. This can crash the client and may permit code execution through attacker-controlled heap corruption. This issue is fixed in version 3.27.0.