CVE-2026-44713 pam_usb: Command injection via $TMUX environment variable leads to RCE as root
Attackers can execute arbitrary commands as root by injecting shell syntax into the TMUX environment variable processed by the pam_usb module.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-44713?
CVE-2026-44713 is a high-severity command injection vulnerability in mcdope pam_usb, published on 27 May 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-44713?
How do I fix CVE-2026-44713?
No fix has been published for CVE-2026-44713 yet. Limit exposure of the affected software until one is available.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2026-44713 being exploited?
There is no known exploitation of CVE-2026-44713 in the wild and no public exploit code.
Sources
Also known as GHSA-822m-whrh-vrj8.