Out-of-bounds Write Affecting freerdp3 package, versions <3.5.1+dfsg1-0ubuntu1.4


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
0.08% (23rd percentile)

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  • Snyk IDSNYK-UBUNTU2404-FREERDP3-15357699
  • published18 Mar 2026
  • disclosed25 Feb 2026

Introduced: 25 Feb 2026

CVE-2026-26955  (opens in a new tab)
CWE-787  (opens in a new tab)

How to fix?

Upgrade Ubuntu:24.04 freerdp3 to version 3.5.1+dfsg1-0ubuntu1.4 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream freerdp3 package and not the freerdp3 package as distributed by Ubuntu. See How to fix? for Ubuntu:24.04 relevant fixed versions and status.

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, a malicious RDP server can trigger a heap buffer overflow in FreeRDP clients using the GDI surface pipeline (e.g., xfreerdp) by sending an RDPGFX ClearCodec surface command with an out-of-bounds destination rectangle. The gdi_SurfaceCommand_ClearCodec() handler does not call is_within_surface() to validate the command rectangle against the destination surface dimensions, allowing attacker-controlled cmd-&gt;left/cmd-&gt;top (and subcodec rectangle offsets) to reach image copy routines that write into surface-&gt;data without bounds enforcement. The OOB write corrupts an adjacent gdiGfxSurface struct's codecs* pointer with attacker-controlled pixel data, and corruption of codecs* is sufficient to reach an indirect function pointer call (NSC_CONTEXT.decode at nsc.c:500) on a subsequent codec command — full instruction pointer (RIP) control demonstrated in exploitability harness. Users should upgrade to version 3.23.0 to receive a patch.

CVSS Base Scores

version 3.1