Bug 2519817 (CVE-2026-55191)

Summary: CVE-2026-55191 FreeRDP: FreeRDP: Arbitrary code execution via heap-buffer-overflow in AVC444 YUV buffer allocation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in FreeRDP. FreeRDP clients that negotiate RDPGFX AVC444 with an H.264 decoder backend are vulnerable to a heap-buffer-overflow. A malicious Remote Desktop Protocol (RDP) server can supply crafted surface dimensions, causing an undersized buffer to be allocated. This can lead to a client crash and potentially allow for arbitrary code execution through attacker-influenced heap corruption.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2521929, 2521933, 2521931    
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Description OSIDB Bzimport 2026-08-19 17:56:55 UTC 
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.