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Vulnerability · Published May 29, 2026 · Assigned by GitHub_M

CVE-2026-44421FreeRDP RDPGFX CacheToSurface heap-buffer-overflow via clamped-rectangle validation bypass

High 8.8

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 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.8High
Exploit odds (30 days)0.5%top 56.5% 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 3.26.0, a malicious RDP server can trigger a heap-buffer-overflow write in the FreeRDP client by sending crafted RDPGFX PDUs. The bug is in gdi_CacheToSurface: it validates a destination rectangle that is clamped to UINT16_MAX, but then performs the copy using the original cacheEntry->width/height. This can cause a large out-of-bounds heap write and may lead to client crashes or code execution. This bug is reachable from a malicious RDP server, but only when the client has RDPGFX enabled. This vulnerability is fixed in 3.26.0.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:10freerdp2:3.10.3-12.el10_2.6ALSA-2026:36203
AlmaLinux:10freerdp-devel2:3.10.3-12.el10_2.6ALSA-2026:36203
AlmaLinux:10freerdp-libs2:3.10.3-12.el10_2.6ALSA-2026:36203
AlmaLinux:10freerdp-server2:3.10.3-12.el10_2.6ALSA-2026:36203
AlmaLinux:10libwinpr2:3.10.3-12.el10_2.6ALSA-2026:36203
AlmaLinux:10libwinpr-devel2:3.10.3-12.el10_2.6ALSA-2026:36203
Debian:12freerdp2no fix listedDEBIAN-CVE-2026-44421
Debian:13freerdp3no fix listedDEBIAN-CVE-2026-44421
Debian:14freerdp33.26.0+dfsg-1DEBIAN-CVE-2026-44421
Rocky Linux:10freerdp2:3.10.3-12.el10_2.6RLSA-2026:36203
Ubuntu:22.04:LTSfreerdp2no fix listedUBUNTU-CVE-2026-44421
Ubuntu:24.04:LTSfreerdp33.30.0+dfsg-0ubuntu0.24.04.1UBUNTU-CVE-2026-44421
Ubuntu:24.04:LTSfreerdp33.30.0+dfsg-0ubuntu0.24.04.1USN-8561-1
Ubuntu:25.10freerdp3no fix listedUBUNTU-CVE-2026-44421
Ubuntu:26.04:LTSfreerdp33.30.0+dfsg-0ubuntu0.26.04.1UBUNTU-CVE-2026-44421
Ubuntu:26.04:LTSfreerdp33.30.0+dfsg-0ubuntu0.26.04.1USN-8561-1

Affected products (as reported)

VendorProductVersions
FreeRDP FreeRDP < 3.26.0

Weakness: CWE-122, CWE-787 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

References