High severity · published Aug 19, 2026
CVE-2026-55192
FreeRDP: Out-of-bounds read in H.264 YUV-to-RGB conversion due to decoder/surface dimension mismatch
8.2
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 39% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FR
FreeRDP · FreeRDP
< 3.27.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-55192
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-55192
Patch
https://github.com/FreeRDP/FreeRDP/commit/0cd45b70bb1fe6befd258ff64c46461947e99adb
Issue Tracking
https://github.com/FreeRDP/FreeRDP/pull/12873
Release Notes
https://github.com/FreeRDP/FreeRDP/releases/tag/3.27.0
Exploit
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-3mmf-qh4f-frm6
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