FreeRDP up to 3.20.x ClearCodec heap-based overflow

CVSS Meta Temp Score
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CTI Interest Score
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8.4$0-$5k0.00

Summaryinfo

A vulnerability has been found in FreeRDP up to 3.20.x and classified as critical. The impacted element is an unknown function of the component ClearCodec. Performing a manipulation results in heap-based overflow. This vulnerability is cataloged as CVE-2026-23534. It is possible to initiate the attack remotely. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in FreeRDP up to 3.20.x. It has been classified as critical. This affects an unknown part of the component ClearCodec. The manipulation with an unknown input leads to a heap-based overflow vulnerability. CWE is classifying the issue as CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.21.0, a client-side heap buffer overflow occurs in the ClearCodec bands decode path when crafted band coordinates allow writes past the end of the destination surface buffer. A malicious server can trigger a client‑side heap buffer overflow, causing a crash (DoS) and potential heap corruption with code‑execution risk depending on allocator behavior and surrounding heap layout. Version 3.21.0 contains a patch for the issue.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-23534 since 01/13/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 297109 (TencentOS Server 4: freerdp (TSSA-2026:0039)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 3.21.0 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (297109), EUVD (EUVD-2026-3314) and CERT Bund (WID-SEC-2026-0145). Be aware that VulDB is the high quality source for vulnerability data.

Affected

  • Open Source FreeRDP

Productinfo

Type

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 8.5
VulDB Meta Temp Score: 8.4

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 9.8
NVD Vector: 🔒

CVSSv2info

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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Heap-based overflow
CWE: CWE-122 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Proof-of-Concept

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 297109
Nessus Name: TencentOS Server 4: freerdp (TSSA-2026:0039)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: FreeRDP 3.21.0

Timelineinfo

01/13/2026 CVE reserved
01/19/2026 +6 days Advisory disclosed
01/19/2026 +0 days VulDB entry created
01/30/2026 +11 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-23534 (🔒)
GCVE (CVE): GCVE-0-2026-23534
GCVE (VulDB): GCVE-100-341799
EUVD: 🔒
CERT Bund: WID-SEC-2026-0145 - FreeRDP: Mehrere Schwachstellen ermöglichen DoS und Codeausführung

Entryinfo

Created: 01/19/2026 19:06
Updated: 01/30/2026 01:01
Changes: 01/19/2026 19:06 (68), 01/19/2026 21:51 (2), 01/20/2026 08:33 (1), 01/20/2026 18:14 (7), 01/29/2026 01:43 (11), 01/30/2026 01:01 (2)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

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