CVE-2026-23531

CRITICAL

9.8

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.

CVE Details

CVSS v3.1 Score9.8

SeverityCRITICAL

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published1/19/2026

Last Modified1/28/2026

Sourcenvd

Honeypot Sightings0

Affected Products

freerdp:freerdp

Weaknesses (CWE)

CWE-122

References

https://github.com/FreeRDP/FreeRDP/blob/38514dfa5813aa945a86cfbcec279033f8394468/libfreerdp/codec/clear.c#L1139-L1145(security-advisories@github.com)

https://github.com/FreeRDP/FreeRDP/releases/tag/3.21.0(security-advisories@github.com)

https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-xj5h-9cr5-23c5(security-advisories@github.com)

IOC Correlations

No correlations recorded

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