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Vulnerability · Published Jan 19, 2026 · Assigned by GitHub_M

CVE-2026-23531FreeRDP has heap-buffer-overflow in clear_decompress

High 7.6

In plain English

A high-severity heap buffer overflow in FreeRDP from FreeRDP. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.6High
Exploit odds (30 days)0.5%top 54.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:10freerdp2:3.10.3-5.el10_1.1ALSA-2026:2222
AlmaLinux:8freerdp2:2.11.7-2.el8_10ALSA-2026:2081
AlmaLinux:9freerdp2:2.11.7-1.el9_7.1ALSA-2026:2048
AlmaLinux:10freerdp-devel2:3.10.3-5.el10_1.1ALSA-2026:2222
AlmaLinux:8freerdp-devel2:2.11.7-2.el8_10ALSA-2026:2081
AlmaLinux:9freerdp-devel2:2.11.7-1.el9_7.1ALSA-2026:2048
AlmaLinux:10freerdp-libs2:3.10.3-5.el10_1.1ALSA-2026:2222
AlmaLinux:8freerdp-libs2:2.11.7-2.el8_10ALSA-2026:2081
AlmaLinux:9freerdp-libs2:2.11.7-1.el9_7.1ALSA-2026:2048
AlmaLinux:10freerdp-server2:3.10.3-5.el10_1.1ALSA-2026:2222
AlmaLinux:10libwinpr2:3.10.3-5.el10_1.1ALSA-2026:2222
AlmaLinux:8libwinpr2:2.11.7-2.el8_10ALSA-2026:2081
AlmaLinux:9libwinpr2:2.11.7-1.el9_7.1ALSA-2026:2048
AlmaLinux:10libwinpr-devel2:3.10.3-5.el10_1.1ALSA-2026:2222
AlmaLinux:8libwinpr-devel2:2.11.7-2.el8_10ALSA-2026:2081
AlmaLinux:9libwinpr-devel2:2.11.7-1.el9_7.1ALSA-2026:2048
Alpine:v3.23freerdp3.22.0-r0ALPINE-CVE-2026-23531
Alpine:v3.24freerdp3.21.0-r0ALPINE-CVE-2026-23531
Debian:12freerdp2no fix listedDEBIAN-CVE-2026-23531
Debian:13freerdp33.15.0+dfsg-2.1+deb13u1DEBIAN-CVE-2026-23531
Debian:14freerdp33.21.0+dfsg-1DEBIAN-CVE-2026-23531
Rocky Linux:10freerdp2:3.10.3-5.el10_1.1RLSA-2026:2222
Rocky Linux:8freerdp2:2.11.7-2.el8_10RLSA-2026:2081
Rocky Linux:9freerdp2:2.11.7-1.el9_7.1RLSA-2026:2048
Ubuntu:22.04:LTSfreerdp22.6.1+dfsg1-3ubuntu2.8USN-8004-1
Ubuntu:22.04:LTSfreerdp22.6.1+dfsg1-3ubuntu2.8UBUNTU-CVE-2026-23531
Ubuntu:24.04:LTSfreerdp33.5.1+dfsg1-0ubuntu1.4USN-8105-1
Ubuntu:24.04:LTSfreerdp33.5.1+dfsg1-0ubuntu1.4UBUNTU-CVE-2026-23531
Ubuntu:25.10freerdp33.16.0+dfsg-2ubuntu0.3UBUNTU-CVE-2026-23531
Ubuntu:25.10freerdp33.16.0+dfsg-2ubuntu0.3USN-8105-1

Affected products (as reported)

VendorProductVersions
FreeRDP FreeRDP < 3.21.0

Weakness: CWE-122 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H

References