Freerdp CVE-2026-25997

CRITICAL

Use After Free (CWE-416)

2026-02-25 security-advisories@github.com

Use After Free Red Hat Freerdp Suse

Critical

Disputed · 9.8 NVD

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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

Access

Establish RDP connection to FreeRDP client
Delivery

Trigger auto-reconnect via network disruption
Exploit

Cliprdr channel frees lastSentFormats array
Execution

X11 event thread accesses freed memory
Impact

Heap corruption and code execution

Vulnerability Assessment

Weakness	CWE CWE-416 OWASP Top 10:2025 A06:2021 - Vulnerable and Outdated Components ASVS 5.0 V15 - Secure Coding and Architecture Memory lifecycle management MITRE ATT&CK 2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Exploitation Conditions	FreeRDP versions prior to 3.23.0 with X11 clipboard support enabled and cliprdr channel active. Attacker must control or intercept RDP server to trigger auto-reconnect sequence causing race condition between cliprdr thread and X11 event thread.
Impact	CVSS 9.8. Five UAFs in a single release indicate systemic memory safety issues in FreeRDP's X11 client.
Exploit ScenarioDerived	RDP server triggers clipboard format negotiation causing UAF for code execution.

Act Now Prioritize within 24-48h. Why: CRITICAL severity + public POC available.

Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Use-after-free in FreeRDP xf_clipboard_format_equal before 3.23.0. Clipboard format comparison uses freed memory. Fifth FreeRDP UAF. PoC and patch available.

Earlier versions of this analysis (1)

v1 Mar 12, 2026 - 21:55 CVSS 9.8

Fifth FreeRDP UAF in clipboard format comparison.

RemediationAI

Update FreeRDP to 3.23.0.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

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Technical ContextAI · show details

CWE-416 UAF in xf_clipboard_format_equal. Format comparison during clipboard operations references freed memory.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

Sources disagree (Medium–Critical)

GitHub Advisory PRIMARY 9.8 CRITICAL

AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

SUSE CRITICAL

Red Hat 5.3 MEDIUM

vuln.today treats the vendor’s rating as authoritative. A higher third-party CVSS (e.g. CISA-ADP) is shown for transparency but does not drive the headline severity.

CVSS VectorGitHub Advisory

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

3

PoC Detected

Feb 27, 2026 - 14:57 vuln.today

Public exploit code

Patch released

Feb 27, 2026 - 14:57 nvd

Patch available

CVE Published

Feb 25, 2026 - 21:16 nvd

CRITICAL 9.8

DescriptionGitHub Advisory

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.

Executive ViewAI

Why It Matters

CVE-2026-25997 is a critical vulnerability in FreeRDP with a CVSS score of 9.8 that enables remote code execution with minimal user interaction. Any organization using FreeRDP for remote access faces immediate risk of system compromise and potential data breach, making this a priority security incident requiring urgent remediation across all affected infrastructure.

Business Impact: Severe

Compensating Controls

Apply vendor patch. If patching cannot be completed immediately: (1) Restrict FreeRDP access using network segmentation and firewall rules to authorized IPs only; (2) Disable FreeRDP on non-essential systems; (3) Implement VPN requirement for all remote access; (4) Enable enhanced monitoring and logging on FreeRDP services; (5) Disable RDP features not required for operations.

Threat Intelligence Overview

EPSS Score

0.1%

Top 75% exploitable

Exploit

POC

Public exploit code exists

Data Quality

4 sources

Confidence: Medium

CVE.org

EPSS Vendor

GitHub

VulDB

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity CRITICAL

CISA KEV No

Public POC Yes

EPSS 0.1%

Patch available Yes

Active threat No

Deciding rule

CRITICAL severity + public POC available

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Out-of-Cycle

Exploitation· derived

Poc

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact

Very High

Priority Score

69

Low Medium High Critical

KEV: 0

EPSS: 0

CVSS: +49

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Use After Free HIGH

Use-after-free vulnerabilities occur when a program continues to access memory through a pointer after that memory has been deallocated.

Affected Products (CPE)GitHub Advisory

cpe:2.3:a:freerdp:freerdp:*:*:*:*:*:*:*:*

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Same weakness CWE-416 – Use After Free

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CVE-2019-0708 CRITICAL POC

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CVE-2014-0322 HIGH POC

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CVE-2009-4324 HIGH POC

CVE-2015-0313 CRITICAL POC

CVE-2015-5122 CRITICAL POC

CVE-2013-2551 HIGH POC

Same technique Use After Free

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CVE-2012-4969 HIGH POC

Vendor StatusVendor

SUSE

Severity: Critical

Product	Status
openSUSE Tumbleweed	Fixed
SUSE Linux Enterprise Desktop 15 SP7	Fixed
SUSE Linux Enterprise Desktop 15 SP7	Fixed
SUSE Linux Enterprise Module for Package Hub 15 SP7	Fixed
SUSE Linux Enterprise Module for Package Hub 15 SP7	Fixed

References

Advisories & patches

PATCH https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L1884 PATCH https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L1889 PATCH https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L265 PATCH https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L616 PATCH https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L831 PATCH https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L851-L855 PATCH https://github.com/FreeRDP/FreeRDP/blob/5c7aae27d0417b42b4806c2a5c583ca39dd9ef1e/client/X11/xf_cliprdr.c#L868-L875 PATCH https://github.com/FreeRDP/FreeRDP/commit/58409406afe7c2a8a71ed2dc8e22075be4f41c0c ADVISORY https://vuldb.com/vuln/347857

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