CVE-2026-25954Public exploitNetwork attack vector

Client crash via unlocked RAIL window lookup

Published Feb 25, 2026 · Updated Feb 25, 2026

Use-after-free in FreeRDP before 3.23.0 allows remote attackers controlling an RDP server to crash X11 clients through RAIL orders. The xf_rail_get_window lookup releases the railWindows hash-table lock before xf_rail_server_local_move_size finishes using the returned xfAppWindow, allowing the main thread to delete and free it concurrently. The client must connect to a RAIL-capable malicious server; demonstrated impact is a crash, while code execution remains unproven.

CVSS severity7.5
High
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in FreeRDP before 3.23.0 allows remote attackers controlling an RDP server to crash X11 clients through RAIL orders. The xf_rail_get_window lookup releases the railWindows hash-table lock before xf_rail_server_local_move_size finishes using the returned xfAppWindow, allowing the main thread to delete and free it concurrently. The client must connect to a RAIL-capable malicious server; demonstrated impact is a crash, while code execution remains unproven.

The record

CVE
CVE-2026-25954
Published
Feb 25, 2026
Updated
Feb 25, 2026
Vendor
FreeRDP
Product
FreeRDP
Classifications
CWE-416, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 3.23.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FreeRDP · FreeRDPversion=< 3.23.0

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.5GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-416Use After Free
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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