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->left`/`cmd->top` (and subcodec rectangle offsets) to reach image copy routines that write into `surface->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.

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Wed, 25 Feb 2026 21:15:00 +0000

Type Values Removed Values Added
Description 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->left`/`cmd->top` (and subcodec rectangle offsets) to reach image copy routines that write into `surface->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.
Title FreeRDP has Out-of-bounds Write
Weaknesses CWE-787
References
Metrics cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-02-25T20:47:14.660Z

Reserved: 2026-02-16T22:20:28.611Z

Link: CVE-2026-26955

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-02-25T21:16:42.863

Modified: 2026-02-25T21:16:42.863

Link: CVE-2026-26955

cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses