Use After Free Affecting freerdp/freerdp package, versions [,3.23.0)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-UNMANAGED-FREERDPFREERDP-15363353
- published27 Feb 2026
- disclosed25 Feb 2026
- creditKim Dong Han
Introduced: 25 Feb 2026
NewCVE-2026-25959 (opens in a new tab)How to fix?
Upgrade freerdp/freerdp to version 3.23.0 or higher.
Overview
Affected versions of this package are vulnerable to Use After Free through the xf_cliprdr_provide_data_() function. An attacker can cause the application to crash or become unresponsive by triggering a heap use-after-free condition during clipboard handling.
PoC
- Build
xfreerdpwith AddressSanitizer enabled. - Start a sample RDP server with
cliprdrsupport that responds toCB_FORMAT_DATA_REQUESTwith dummy UTF-16LE data, and disconnects after 3 seconds to trigger auto-reconnect. - Connect with
xfreerdp /v:127.0.0.1:13390 /u:a /p:a /cert:ignore +clipboard +auto-reconnect /auto-reconnect-max-retries:20. - Concurrently spam clipboard writes (
xclip -selection clipboard) and reads (xclip -o -selection clipboard) to provoke format list re-sends (clearing the cache) and selection requests (triggering data responses). - The cliprdr channel thread uses
pDstDatainXChangePropertyafter the X11 thread freed it viaHashTable_Clear— ASan detects heap-use-after-free inmemcpyinsideXChangeProperty.