CVE-2026-55626 in xrdp
Summary
by MITRE • 07/20/2026
xrdp is an open source RDP server. In versions 0.10.6 and prior, when an authenticated user session is initialized using the Xvnc backend over UNIX domain sockets, the Xvnc process is launched with insufficient authentication mechanisms. A local authenticated attacker could exploit this vulnerability to bypass intended session isolation, allowing them to unauthorizedly view or control the active desktop sessions of other users on the same system. Users using other backends, such as xorgxrdp or Xvnc over TCP sockets, are not affected. This issue has been fixed in version 0.10.6.1.
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Analysis
by VulDB Data Team • 07/20/2026
The xrdp vulnerability represents a critical session isolation flaw that undermines the security model of remote desktop services through inadequate authentication mechanisms during process initialization. This vulnerability specifically affects versions 0.10.6 and earlier where the Xvnc backend implementation fails to properly secure inter-process communications when establishing authenticated user sessions. The flaw occurs within the UNIX domain socket communication channel that facilitates desktop session management, creating an attack surface that allows local authenticated users to exploit insufficient access controls. The vulnerability stems from improper privilege separation and authentication enforcement during the Xvnc process launch sequence, where the system fails to implement adequate isolation measures between concurrent user sessions.
The technical exploitation of this vulnerability leverages the weak authentication mechanisms inherent in the UNIX domain socket communication path used by the Xvnc backend. When an authenticated user establishes a session through this specific backend configuration, the launched Xvnc process operates without proper access controls that would normally prevent cross-user interference. This creates a scenario where malicious users can potentially intercept or manipulate Xvnc communications to gain unauthorized access to other active desktop sessions. The attack vector specifically targets the local authenticated threat model where attackers already possess legitimate credentials but seek to escalate their privileges through session hijacking techniques. The vulnerability manifests as a failure in the security boundary enforcement that should normally separate user sessions, allowing for unauthorized viewing or control of other users' desktop environments.
This security weakness has significant operational impact on systems relying on xrdp with Xvnc backend configurations, particularly in multi-user environments where session isolation is paramount for maintaining data confidentiality and system integrity. Organizations utilizing affected versions face potential exposure to privilege escalation attacks, unauthorized data access, and potential system compromise through desktop session manipulation. The vulnerability directly violates security principles related to least privilege and proper resource isolation, as it allows lateral movement within the same host environment without requiring additional authentication factors or elevated privileges. Systems where multiple users share the same physical infrastructure are particularly vulnerable, creating scenarios where a compromised user account could potentially access or manipulate other users' active sessions.
The mitigation strategy for this vulnerability involves upgrading to xrdp version 0.10.6.1 or later, which implements proper authentication mechanisms during Xvnc process initialization. Organizations should also consider implementing alternative backend configurations such as xorgxrdp or Xvnc over TCP sockets, which remain unaffected by this specific flaw. Security administrators should conduct comprehensive vulnerability assessments to identify systems running affected versions and ensure proper patch management procedures are in place. The fix addresses the underlying authentication deficiency by implementing proper access control enforcement during session establishment, ensuring that each user session operates with appropriate isolation boundaries. This remediation aligns with security frameworks such as CWE-284 (Improper Access Control) and addresses ATT&CK techniques related to privilege escalation and credential access through local system manipulation. Organizations should also review their network segmentation policies to ensure additional layers of defense are maintained even when using alternative backends that may not be vulnerable to this specific flaw.