CVE-2026-105773 in ClamXAV
Summary
by MITRE • 10/06/2026
Canimaan Software ClamXAV versions 3.3 - 3.11 contains a local privilege escalation vulnerability in the Privileged Helper Tool caused by a race condition and insufficient file validation, allowing a local attacker to execute arbitrary code with system privileges. Fixed in 3.11.1.
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Analysis
by VulDB Data Team • 10/06/2026
The security flaw identified within Canimaan Software ClamXAV versions ranging from 3.3 through 3.11 represents a critical local privilege escalation vulnerability located specifically within the application's Privileged Helper Tool. This component is designed to perform administrative tasks that require elevated permissions, such as scanning files in protected system directories or updating virus definitions. The core of the issue stems from two distinct technical deficiencies: a race condition and insufficient file validation during the handling of temporary files or configuration updates. When the helper tool processes these operations, it fails to adequately verify the integrity and ownership of the target paths before writing data. This oversight creates a window of opportunity for an attacker who has already gained local access to the system to manipulate the filesystem in a way that forces the privileged process to write executable code into a location where it will be executed with root or administrator privileges upon the next invocation by the helper tool.
From a technical perspective, this vulnerability aligns closely with CWE-362, which describes concurrent execution race conditions involving shared resources without proper synchronization. In this specific context, the attacker exploits the timing gap between when the application determines the target file path and when it actually performs the write operation. By rapidly creating or modifying files in predictable directories, such as temporary folders or user-writable configuration paths, a local user can trick the helper tool into overwriting critical binaries or scripts with malicious payloads. This is further compounded by CWE-732, which pertains to incorrect permission assignment for privileged functions. The lack of strict validation means that the application does not sufficiently check if the file it intends to modify is under its control or if an attacker has substituted a symlink or created a new file in the expected location with malicious intent.
The operational impact of this vulnerability is severe because it allows any local user, regardless of their initial privilege level, to escalate their rights to that of the system administrator or root user. Once an attacker achieves this elevated status, they gain unrestricted access to all files on the machine, including sensitive personal data, corporate secrets, and security configurations. They can install persistent backdoors, disable other security controls such as firewalls or endpoint protection agents, and move laterally across a network if the compromised host serves as a gateway. This effectively neutralizes many perimeter defenses because the attacker operates from within with full system authority, making detection significantly more difficult for standard monitoring tools that do not specifically audit privilege escalation events in helper daemons.
This type of vulnerability is frequently associated with MITRE ATT&CK technique T1068, which covers Exploitation for Privilege Escalation, and often involves techniques related to binary planting or DLL hijacking depending on the specific execution mechanism used by the attacker. The failure to implement secure coding practices such as atomic file operations, strict path canonicalization, and proper use of temporary directory permissions with restrictive umask settings is a common root cause in macOS helper tools that have historically been targeted for privilege escalation attacks. Organizations relying on ClamXAV must recognize that while antivirus software provides essential protection against external threats, the integrity of its own privileged components is paramount to maintaining overall system security posture.
To mitigate this risk, immediate action should be taken by upgrading Canimaan Software ClamXAV to version 3.11.1 or any later release where these issues have been addressed. The vendor has implemented fixes that likely include stricter validation of file paths before writing operations and improved synchronization mechanisms to prevent race conditions during privileged tasks. In the interim, administrators should ensure that local user accounts are restricted as much as possible through principle of least privilege policies. Additionally, monitoring for unusual activity in system logs related to helper tool executions or unexpected changes in protected directories can help detect exploitation attempts early. Regular auditing of installed software and keeping all security tools up to date is essential to closing these types of gaps that allow local users to compromise the entire host environment.