CVE-2026-44709 pam_usb: PINENTRY_FALLBACK_APP environment variable allows arbitrary command execution
Attackers can execute arbitrary commands with elevated privileges by manipulating the PINENTRY_FALLBACK_APP environment variable in pam_usb.
- 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-2026-44709?
CVE-2026-44709 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, pamusb-pinentry reads the PINENTRY_FALLBACK_APP environment variable and executes it directly without any validation. Any process that can set environment variables before pamusb-pinentry is invoked can point PINENTRY_FALLBACK_APP at an arbitrary binary or script and have it executed with the privileges of the pam_usb tool chain. This vulnerability is fixed in 0.8.7.
Weakness: CWE-78
Which versions are affected by CVE-2026-44709?
How do I fix CVE-2026-44709?
No fix has been published for CVE-2026-44709 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-2026-44709 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-44709 exists.
Sources
Also known as GHSA-jxrj-q67x-wr4c.