mcdope pam_usb up to 0.8.6 on Linux socket-path src/tmux.c popen TMUX os command injection

Summaryinfo

A vulnerability identified as critical has been detected in mcdope pam_usb up to 0.8.6 on Linux. This issue affects the function popen of the file src/tmux.c of the component socket-path. The manipulation of the argument TMUX leads to os command injection. This vulnerability is uniquely identified as CVE-2026-44713. Local access is required to approach this attack. No exploit exists. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in mcdope pam_usb up to 0.8.6 on Linux and classified as critical. This issue affects the function popen of the file src/tmux.c of the component socket-path. The manipulation of the argument TMUX with an unknown input leads to a os command injection vulnerability. Using CWE to declare the problem leads to CWE-78. The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

pam_usb provides hardware authentication for Linux using ordinary removable media. Prior to 0.8.7, src/tmux.c reads the user's $TMUX environment variable, splits it on commas, and interpolates the socket-path component directly into a shell command passed to popen(). Because the value is placed inside double-quotes without sanitisation, any value containing " terminates the quoted string and injects arbitrary shell syntax. popen() runs as root inside the PAM stack. This vulnerability is fixed in 0.8.7.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-44713 since 05/07/2026. The exploitation is known to be easy. An attack has to be approached locally. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1202 for this issue.

Upgrading to version 0.8.7 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-32657). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Productinfo

Vendor

• mcdope

Name

• pam_usb

Version

• 0.8.0
• 0.8.1
• 0.8.2
• 0.8.3
• 0.8.4
• 0.8.5
• 0.8.6

Website

• Product: https://github.com/mcdope/pam_usb/

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If you want to get the best quality for vulnerability data then you always have to consider VulDB.

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