CVE-2026-55639
xrdp: Out-of-bounds read in GCC Conference Create Request CS_SECURITY processing (xrdp_sec_process_mcs_data_CS_SECURITY)
Description
xrdp is an open source RDP server. Versions 0.10.6 and prior contain a vulnerability concerning the parsing of Client Security Data within the Client MCS Connect Initial PDU with GCC Conference Create Request during the connection sequence. During the initial capability and security negotiation phase, the parser fails to perform sufficient length validation for the incoming data block. A remote, unauthenticated attacker could potentially exploit this flaw by sending a specially crafted RDP packet containing malformed data. Due to missing bounds checks, the xrdp process may read a small number of bytes beyond the declared data block boundary, potentially disclosing process memory contents that could be combined with other vulnerabilities. This issue has been fixed in version 0.10.6.1.
INFO
Published Date :
July 20, 2026, 6:16 p.m.
Last Modified :
Oct. 24, 2026, 8:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE |
Solution
- Update xrdp to version 0.10.6.1 or later.
- Apply security patches provided by the vendor.
- Validate secure configuration of xrdp service.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-55639.
| URL | Resource |
|---|---|
| https://github.com/neutrinolabs/xrdp/releases/tag/v0.10.6.1 | Product Release Notes |
| https://github.com/neutrinolabs/xrdp/security/advisories/GHSA-6g36-mxcf-r3gc | Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-55639 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-55639
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-55639 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-55639 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 24, 2026
Action Type Old Value New Value Added Translation Title: xrdp de neutrinolabs, Description: xrdp es un servidor RDP de código abierto. Las versiones 0.10.6 y anteriores contienen una vulnerabilidad relacionada con el análisis de los datos de seguridad del cliente dentro de la PDU inicial de conexión MCS del cliente con la solicitud de creación de conferencia GCC durante la secuencia de conexión. Durante la fase inicial de negociación de capacidades y seguridad, el analizador no realiza una validación de longitud suficiente para el bloque de datos entrante. Un atacante remoto no autenticado podría potencialmente explotar esta falla enviando un paquete RDP especialmente diseñado que contenga datos malformados. Debido a la falta de comprobaciones de límites, el proceso xrdp puede leer un pequeño número de bytes más allá del límite del bloque de datos declarado, revelando potencialmente el contenido de la memoria del proceso que podría combinarse con otras vulnerabilidades. Este problema ha sido solucionado en la versión 0.10.6.1. -
Initial Analysis by [email protected]
Jul. 29, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:neutrinolabs:xrdp:*:*:*:*:*:*:*:* versions up to (excluding) 0.10.6.1 Added Reference Type GitHub, Inc.: https://github.com/neutrinolabs/xrdp/releases/tag/v0.10.6.1 Types: Product, Release Notes Added Reference Type GitHub, Inc.: https://github.com/neutrinolabs/xrdp/security/advisories/GHSA-6g36-mxcf-r3gc Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 20, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-55639', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-20T19:01:32.890448Z'} -
New CVE Received by [email protected]
Jul. 20, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'neutrinolabs', 'product': 'xrdp', 'versions': [{'status': 'affected', 'version': '< 0.10.6.1'}]}] Added Description xrdp is an open source RDP server. Versions 0.10.6 and prior contain a vulnerability concerning the parsing of Client Security Data within the Client MCS Connect Initial PDU with GCC Conference Create Request during the connection sequence. During the initial capability and security negotiation phase, the parser fails to perform sufficient length validation for the incoming data block. A remote, unauthenticated attacker could potentially exploit this flaw by sending a specially crafted RDP packet containing malformed data. Due to missing bounds checks, the xrdp process may read a small number of bytes beyond the declared data block boundary, potentially disclosing process memory contents that could be combined with other vulnerabilities. This issue has been fixed in version 0.10.6.1. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N Added CWE CWE-125 Added Reference https://github.com/neutrinolabs/xrdp/releases/tag/v0.10.6.1 Added Reference https://github.com/neutrinolabs/xrdp/security/advisories/GHSA-6g36-mxcf-r3gc