CVE-2026-55192
HighCVSS 7.2Summary
In FreeRDP before 3.27.0, H.264 decoder backends can return YUV planes sized from the bitstream without comparing to the RDPGFX surface dimensions. A malicious RDP server can provide an AVC420 or AVC444 bitstream with a smaller decoded frame, causing out-of-bounds reads in the decoder. This can disclose client memory or crash the client.
Risk Assessment
A malicious RDP server can access client memory or cause a crash, compromising confidentiality and availability.
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 H.264 decoder backends can return YUV planes sized from the bitstream without comparing the decoded width and height to the RDPGFX surface dimensions used to validate region rectangles. A malicious RDP server can provide an AVC420 or AVC444 bitstream whose decoded frame is smaller than the negotiated surface, causing yuv420_context_decode and the YUV-to-RGB conversion paths to read beyond the decoder-owned planes in libfreerdp/codec/h264.c and the selected H.264 backend. This can disclose client memory or crash the client. This issue is fixed in version 3.27.0.