CVE-2026-55191

FreeRDP: Heap-buffer-overflow write in AVC444 YUV buffer allocation

State: Published
Severity: 8.7 High
Published: Aug 19, 2026
Updated: Aug 19, 2026
Reserved: Jun 16, 2026

Description

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, FreeRDP clients that negotiate RDPGFX AVC444 with an H.264 decoder backend calculate the intermediate YUV444 allocation size in libfreerdp/codec/h264.c with 32-bit multiplication in avc444_ensure_buffer. A malicious RDP server can supply surface dimensions for which piDstStride multiplied by padDstHeight wraps to a small nonzero value, causing winpr_aligned_recalloc to allocate an undersized buffer before YUV420CombineToYUV444 writes using the actual stride and rectangle dimensions. This can cause a client crash and may permit code execution through attacker-influenced heap corruption. This issue is fixed in version 3.27.0.

Scores

CVSS	Score	Vector	Source
4.0	8.7 High	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N	GitHub_M

Weaknesses

CWE-122 Heap-based Buffer Overflow
CWE-190 Integer Overflow or Wraparound

Affected Products

Product	Versions
FreeRDPFreeRDP	< 3.27.0Affected

References

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