CVE-2026-55191

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.

CVSS 4.0

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

CVSS 3.1

9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

0.6% chance of exploitation in the next 30 days; higher than 49% of CVEs (scores of 2026-10-25)

CWEs

CWE-122, CWE-190

Published

2026-08-19

Modified

2026-10-26

Record from

the NVD, synced 2026-10-26

Affected

• freerdp:freerdp

References

• https://github.com/FreeRDP/FreeRDP/commit/97f40b9e766af375f4e41ac6a3f4397d708d249c
• 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-vx73-w5q6-7jqr
• https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-vx73-w5q6-7jqr

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