CVE-2026-44713
pam_usb: Command injection via $TMUX environment variable leads to RCE as root
CVSS Score
8.8
EPSS Score
0.0%
EPSS Percentile
7th
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.
| CWE | CWE-78 CWE-116 |
| Vendor | mcdope |
| Product | pam_usb |
| Published | May 27, 2026 |
| Last Updated | May 30, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High
Affected Versions
mcdope / pam_usb
< 0.8.7