Copyright © 2012 Red Hat, Inc. All rights reserved. Important 2026-08-19T17:51:19 FreeRDP: FreeRDP: Out-of-bounds read leads to memory disclosure or client crash 8.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H CWE-125

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.

A flaw was found in FreeRDP. A malicious Remote Desktop Protocol (RDP) server can provide a specially crafted H.264 video stream that causes the client's H.264 decoder to read beyond its allocated memory. This out-of-bounds read can lead to the disclosure of sensitive client memory or cause the client application to crash, resulting in a denial of service.

An out-of-bounds memory read flaw was found in FreeRDP's H.264 video decoder (`libfreerdp/codec/h264.c`). When handling AVC420 or AVC444 bitstreams, decoder backends fail to validate frame dimensions against negotiated RDPGFX surface boundaries. A malicious RDP server can send a video frame smaller than the surface, causing `yuv420_context_decode` and YUV-to-RGB conversion paths to read past allocated memory buffers. This allows an untrusted server to exfiltrate sensitive client memory contents or crash the client application. To mitigate this vulnerability, disable H.264 graphics acceleration in client connection parameters (e.g., omitting `/gfx:avc420` or `/gfx:avc444` in `xfreerdp`) to force legacy RemoteFX or standard software bitmap rendering. Red Hat Enterprise Linux 10 Affected freerdp Red Hat Enterprise Linux 6 Not affected freerdp Red Hat Enterprise Linux 7 Affected freerdp Red Hat Enterprise Linux 8 Not affected freerdp Red Hat Enterprise Linux 9 Affected freerdp https://www.cve.org/CVERecord?id=CVE-2026-55192 https://nvd.nist.gov/vuln/detail/CVE-2026-55192 https://github.com/FreeRDP/FreeRDP/commit/0cd45b70bb1fe6befd258ff64c46461947e99adb https://github.com/FreeRDP/FreeRDP/pull/12873 https://github.com/FreeRDP/FreeRDP/releases/tag/3.27.0 https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-3mmf-qh4f-frm6