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.

Project Subscriptions

Vendors Products
Freerdp Subscribe
Freerdp Subscribe
Advisories
Source ID Title
Ubuntu USN Ubuntu USN USN-8561-1 FreeRDP vulnerabilities
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 19 Aug 2026 20:00:00 +0000

Type Values Removed Values Added
First Time appeared Freerdp
Freerdp freerdp
Vendors & Products Freerdp
Freerdp freerdp

Wed, 19 Aug 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Wed, 19 Aug 2026 18:00:00 +0000

Type Values Removed Values Added
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.
Title FreeRDP: Heap-buffer-overflow write in AVC444 YUV buffer allocation
Weaknesses CWE-122
CWE-190
References
Metrics cvssV4_0

{'score': 8.7, 'vector': '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'}


Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-19T18:17:07.147Z

Reserved: 2026-06-16T15:20:43.086Z

Link: CVE-2026-55191

cve-icon Vulnrichment

Updated: 2026-08-19T18:16:09.730Z

cve-icon NVD

Status : Received

Published: 2026-08-19T18:16:44.427

Modified: 2026-08-19T19:17:19.833

Link: CVE-2026-55191

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-19T19:45:03Z

Weaknesses