CVE-2026-26986Public exploitNetwork attack vector

Client crash via dangling RAIL window entry

Published Feb 25, 2026 · Updated Feb 25, 2026

Heap use-after-free in FreeRDP before 3.23.0 allows malicious RDP servers to crash Linux X11 clients through a crafted RAIL window title. The xf_rail_window_common error path frees an xfAppWindow after failed title conversion without removing its railWindows hash entry, so disconnect cleanup dereferences and frees the dangling pointer again. The server-controlled path requires the X11 client, RAIL mode, and the built-in strict Unicode converter; a client crash is demonstrated, while code execution depends on allocator behavior and heap layout.

CVSS severity7.5
High
EPSS probability0.48%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap use-after-free in FreeRDP before 3.23.0 allows malicious RDP servers to crash Linux X11 clients through a crafted RAIL window title. The xf_rail_window_common error path frees an xfAppWindow after failed title conversion without removing its railWindows hash entry, so disconnect cleanup dereferences and frees the dangling pointer again. The server-controlled path requires the X11 client, RAIL mode, and the built-in strict Unicode converter; a client crash is demonstrated, while code execution depends on allocator behavior and heap layout.

The record

CVE
CVE-2026-26986
Published
Feb 25, 2026
Updated
Feb 25, 2026
Vendor
FreeRDP
Product
FreeRDP
Classifications
CWE-416, T1499
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

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
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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
T1499Endpoint Denial of Service

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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