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Vulnerability · Published Mar 30, 2026 · Assigned by GitHub_M

CVE-2026-33986FreeRDP: H.264 YUV Buffer Dimension Desync - Heap OOB Write

High 7.5

In plain English

A high-severity heap buffer overflow in FreeRDP from FreeRDP. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 19% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High
Exploit odds (30 days)0.3%top 80.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.24.2, in yuv_ensure_buffer() in libfreerdp/codec/h264.c, h264->width and h264->height are updated before the reallocation loop. If any winpr_aligned_recalloc() call fails, the function returns FALSE but width/height are already inflated. This issue has been patched in version 3.24.2.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.23freerdp3.24.2-r0ALPINE-CVE-2026-33986
Alpine:v3.24freerdp3.24.2-r0ALPINE-CVE-2026-33986
Debian:12freerdp2no fix listedDEBIAN-CVE-2026-33986
Debian:13freerdp33.15.0+dfsg-2.1+deb13u2DEBIAN-CVE-2026-33986
Debian:14freerdp33.24.2+dfsg-1DEBIAN-CVE-2026-33986
Ubuntu:22.04:LTSfreerdp2no fix listedUBUNTU-CVE-2026-33986
Ubuntu:24.04:LTSfreerdp33.30.0+dfsg-0ubuntu0.24.04.1USN-8561-1
Ubuntu:24.04:LTSfreerdp33.30.0+dfsg-0ubuntu0.24.04.1UBUNTU-CVE-2026-33986
Ubuntu:25.10freerdp3no fix listedUBUNTU-CVE-2026-33986
Ubuntu:26.04:LTSfreerdp33.30.0+dfsg-0ubuntu0.26.04.1USN-8561-1

Affected products (as reported)

VendorProductVersions
FreeRDP FreeRDP < 3.24.2

Weakness: CWE-122, CWE-131 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

References