FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, xf_cliprdr_provide_data_ passes freed pDstData to XChangeProperty because the cliprdr channel thread calls xf_cliprdr_server_format_data_response which converts and uses the clipboard data without holding any lock, while the X11 event thread concurrently calls xf_cliprdr_clear_cached_data → HashTable_Clear which frees the same data via xf_cached_data_free, triggering a heap use after free. Version 3.23.0 fixes the issue.
CVE-2026-25959
CRITICALNVD 9.89.8Trending — 3 sources updated this week
EchelonGraph scoreLOW confidence
This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: nvd
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.8Exploit: None knownExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 9.8
- EG Score
- 9.8(low)
- EG Risk
- 49(Track)EG Risk 49/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity98% × 45%Exploitation0% × 40%Automatability30% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 1%
- EPSS %ILE
- 44%
- KEV
- Not listed
Published
February 25, 2026
Last Modified
June 17, 2026
Advisory Details (9)
Auto-updated Jul 27, 2026🔬 Proof of concept available. Patch available. Sources: github_commit, github.
github Patch Available🟡 PoC Available
Heap-use-after-free in xf_cliprdr_provide_data_ · Advisory · FreeRDP/FreeRDP · GitHub
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-78xg-v4p2-4w3cgithub_commit
commit d3e8b3b9365b (FreeRDP/FreeRDP)
Fix landed in FreeRDP/FreeRDP commit d3e8b3b9365b — awaiting tagged release
https://github.com/FreeRDP/FreeRDP/commit/d3e8b3b9365be96a4f11dda149d71b3287227d0ageneric
FreeRDP/client/X11/xf_cliprdr.c at 5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e · FreeRDP/FreeRDP · GitHub
https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L933generic
FreeRDP/client/X11/xf_cliprdr.c at 5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e · FreeRDP/FreeRDP · GitHub
https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L2363generic
FreeRDP/client/X11/xf_cliprdr.c at 5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e · FreeRDP/FreeRDP · GitHub
https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L2323-L2334generic
FreeRDP/client/X11/xf_cliprdr.c at 5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e · FreeRDP/FreeRDP · GitHub
https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L2295generic
FreeRDP/client/X11/xf_cliprdr.c at 5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e · FreeRDP/FreeRDP · GitHub
https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L200-L208generic
FreeRDP/client/X11/xf_cliprdr.c at 5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e · FreeRDP/FreeRDP · GitHub
https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L1337-L1344generic
FreeRDP/client/X11/xf_cliprdr.c at 5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e · FreeRDP/FreeRDP · GitHub
https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L1229-L1243Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 6× in last 7d / 6× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-08-01 04:16 UTCEPSS rescore
- 2026-07-30 16:27 UTCEPSS rescore
- 2026-07-30 01:30 UTCEPSS rescore
- 2026-07-28 15:36 UTCEPSS rescore
- 2026-07-27 14:04 UTCEG score recompute
- 2026-07-27 13:57 UTCOSV refresh
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-25959?
CVE-2026-25959 is a critical vulnerability published on February 25, 2026. FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, xfcliprdrprovidedata passes freed pDstData to XChangeProperty because the cliprdr channel thread calls xfcliprdrserverformatdataresponse which converts and uses the clipboard data without holding any lock,…
When was CVE-2026-25959 disclosed?
CVE-2026-25959 was first published in the National Vulnerability Database on February 25, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-25959 actively exploited?
CVE-2026-25959 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 56.2% of all scored CVEs.
What is the CVSS score of CVE-2026-25959?
CVE-2026-25959 has a CVSS v3 base score of 9.8 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-25959?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-25959, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
Explore the affected products and dependency analysis for CVE-2026-25959
Is Your Infrastructure Affected by CVE-2026-25959?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.