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  4. CVE 2026 55191 freerdp heap buffer overflow write in avc444 yuv
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Back to active CVEs
High · CVSS 8.7CVE-2026-55191

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

Answer in brief

CVE-2026-55191 records a High severity (CVSS 8.7) vulnerability in FreeRDP: Heap-buffer-overflow write in AVC444 YUV buffer allocation. The current sources do not mark it as known exploited. The current feed maps FreeRDP/FreeRDP (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 19, 2026Updated Sep 22, 2026Source checked Oct 3, 2026First seen by HOL Aug 19, 2026Material review Sep 22, 2026
Upstream Advisory

Key facts

Risk
High · CVSS 8.7
Exploitation
Not marked as known exploited
Affected software
2 mapped packages or products
Fix availability
Available

Why this deserves its current priority

CVSS is 8.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps FreeRDP/FreeRDP (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
ProductAffected versionsFixed versions
cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*Not reportedNot reported
Mapped affected packages and fixed versions
PackageAffected rangeFixed version
FreeRDP/FreeRDPgeneric<3.27.03.27.0

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for FreeRDP/FreeRDP.
  2. 2Review the reported fix. Update FreeRDP/FreeRDP to 3.27.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

  1. Published upstream

    Aug 19, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Sep 22, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Aug 19, 2026

Sources and claim methodology

  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
  • GitHub security advisorygithub.com
Upstream source 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.

Quoted source text, attributed separately from HOL analysis.

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Record context

Vulnerability class
Vulnerability
EPSS
Not reported
CWE IDs
CWE-122, CWE-190
Source
CVE List V5
Source checked
Oct 3, 2026
References
4 linked sources
Open source record