CVE-2026-55192

FreeRDP: Out-of-bounds read in H.264 YUV-to-RGB conversion due to decoder/surface dimension mismatch

HIGH
8.2
CVSS Score
Published: August 19, 2026 at 05:51 PM UTC
Updated: October 26, 2026 at 11:10 AM UTC
1 product affected across 1 vendorFreeRDP

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Severity
HIGH8.2
Exploit prediction
EPSS 0.4%
SSVC
PoC

Description

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.27.0, FreeRDP H.264 decoder backends can return YUV planes sized from the bitstream without comparing the decoded width and height to the RDPGFX surface dimensions used to validate region rectangles. A malicious RDP server can provide an AVC420 or AVC444 bitstream whose decoded frame is smaller than the negotiated surface, causing yuv420_context_decode and the YUV-to-RGB conversion paths to read beyond the decoder-owned planes in libfreerdp/codec/h264.c and the selected H.264 backend. This can disclose client memory or crash the client. This issue is fixed in version 3.27.0.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 3.27.0
Affected range stops below 3.27.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (4)

x_refsource_CONFIRMExploitMitigationVendor Advisory
Source: cverecord
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-3mmf-qh4f-frm6
x_refsource_MISCIssue TrackingPatch
Source: cverecord
https://github.com/FreeRDP/FreeRDP/pull/12873
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/FreeRDP/FreeRDP/releases/tag/3.27.0

SSVC — Action Prioritization

SSVCPoCAutomatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-125

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