CVE-2026-25955: FreeRDP has heap-use-after-free in xf_AppUpdateWindowFromSurface (stale XImage)

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-02-25 · updated 2026-06-17
Weakness: CWE-416

Description

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, `xf_AppUpdateWindowFromSurface` reuses a cached `XImage` whose `data` pointer references a freed RDPGFX surface buffer, because `gdi_DeleteSurface` frees `surface->data` without invalidating the `appWindow->image` that aliases it. Version 3.23.0 fixes the issue.

Affected products

FreeRDP: before 3.23.0 — fixed in 3.23.0

How to fix

Upgrade to a fixed version: FreeRDP 3.23.0. Check the vendor advisory for mitigations.

References

https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_window.c#L1484-L1492
https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_window.c#L1494-L1500
https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_window.c#L1528
https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/libfreerdp/gdi/gfx.c#L1224-L1227
https://github.com/FreeRDP/FreeRDP/commit/169d358734509e82663a0d6a0085ae726d439d8e
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-4g54-x8v7-559x
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-4g54-x8v7-559x

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