CVE-2010-0926 in Samba
Summary
by MITRE
The default configuration of smbd in Samba before 3.3.11, 3.4.x before 3.4.6, and 3.5.x before 3.5.0rc3, when a writable share exists, allows remote authenticated users to leverage a directory traversal vulnerability, and access arbitrary files, by using the symlink command in smbclient to create a symlink containing .. (dot dot) sequences, related to the combination of the unix extensions and wide links options.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 05/02/2026
The vulnerability described in CVE-2010-0926 represents a critical directory traversal flaw within the Samba file sharing implementation that affects multiple versions of the software. This issue specifically impacts the smbd daemon which handles SMB/CIFS file sharing protocols, creating a significant security risk for organizations relying on Samba for network file sharing services. The vulnerability stems from improper handling of symbolic links within the context of writable shares, where the combination of unix extensions and wide links configuration options creates an exploitable condition that allows authenticated attackers to bypass normal file access controls.
The technical exploitation of this vulnerability occurs through the smbclient utility where authenticated users can leverage the symlink command to create symbolic links containing .. (dot dot) sequences. This manipulation exploits the way Samba processes these sequences when unix extensions are enabled, allowing attackers to traverse the file system beyond the intended share boundaries. The flaw exists because the system fails to properly validate or sanitize the paths when processing symbolic links, particularly when the wide links option is enabled, which permits access to files outside of the share root directory. This combination creates a path traversal condition that can be exploited to access arbitrary files on the system, potentially exposing sensitive data, configuration files, or system resources.
The operational impact of this vulnerability extends beyond simple unauthorized file access, as it can enable attackers to escalate their privileges and potentially gain deeper system access. An authenticated attacker with write permissions to a share can create symbolic links that point to system files, configuration directories, or other sensitive locations, effectively breaking the isolation that should exist between different shares or user access levels. This vulnerability particularly affects environments where Samba serves as a primary file sharing solution and where writable shares are configured with the wide links option enabled, making it a significant concern for network administrators managing file servers. The attack vector requires only authentication to the SMB service, making it accessible to users who have legitimate access to the file sharing service but should not have access to all system files.
Organizations should immediately implement mitigations including disabling the wide links option when writable shares are configured, ensuring that unix extensions are properly configured to prevent path traversal, and applying the relevant security patches released by Samba developers. The vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, and can be categorized under ATT&CK technique T1078 for valid accounts and T1566 for spearphishing attachments, as attackers may use this vulnerability to gain access to sensitive files that could be used for further exploitation. System administrators should also implement monitoring for unusual symbolic link creation activities and review share configurations to ensure that the wide links option is disabled for writable shares unless absolutely necessary. The recommended solution involves updating to patched versions of Samba where this vulnerability has been addressed through proper input validation and path resolution handling, ensuring that symbolic link processing does not allow traversal beyond intended share boundaries.