What’s Vulnerable › Vulnerabilities

CVE-2026-25997: FreeRDP has heap-use-after-free in xf_clipboard_format_equal

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% 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_clipboard_format_equal` reads freed `lastSentFormats` memory because `xf_clipboard_formats_free` (called from the cliprdr channel thread during auto-reconnect) frees the array while the X11 event thread concurrently iterates it in `xf_clipboard_changed`, triggering a heap use after free. 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_cliprdr.c#L1884
• https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L1889
• https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L265
• https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L616
• https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L831
• https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L851-L855
• https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L868-L875
• https://github.com/FreeRDP/FreeRDP/commit/58409406afe7c2a8a71ed2dc8e22075be4f41c0c
• https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-q5j3-m6jf-3jq4
• https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-q5j3-m6jf-3jq4

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