Critical severity · published Jan 19, 2026
CVE-2026-23531
FreeRDP is a free implementation of the Remote Desktop Protocol
9.8
CVSS
0.5%
EPSS
No
On KEV
Description
FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, in ClearCodec, when `glyphData` is present, `clear_decompress` calls `freerdp_image_copy_no_overlap` without validating the destination rectangle, allowing an out-of-bounds read/write via crafted RDPGFX surface updates. A malicious server can trigger a client‑side heap buffer overflow, causing a crash (DoS) and potential heap corruption with code‑execution risk depending on allocator behavior and surrounding heap layout. Version 3.21.0 contains a patch for the issue.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 45% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FR
Freerdp · Freerdp
before 3.21.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-23531
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-23531
Product
https://github.com/FreeRDP/FreeRDP/blob/38514dfa5813aa945a86cfbcec279033f8394468/libfreerdp/codec/clear.c#L1139-L1145
Release Notes
https://github.com/FreeRDP/FreeRDP/releases/tag/3.21.0
Exploit
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-xj5h-9cr5-23c5
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:2048
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:2081
access.redhat.com
https://access.redhat.com/errata/RHSA-2026:2222
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