CVE-2026-44713

pam_usb: Command injection via $TMUX environment variable leads to RCE as root

HIGH
8.8
CVSS Score
Published: May 27, 2026 at 08:13 PM UTC
Updated: October 26, 2026 at 12:10 PM UTC
1 product affected across 1 vendorPam USB

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Severity
HIGH8.8
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.8.7
Affected range stops below 0.8.7, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

References (1)

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.8HIGHGitHub_M
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-78CWE-116

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