CVE-2026-44709

pam_usb: PINENTRY_FALLBACK_APP environment variable allows arbitrary command execution

HIGH
7.8
CVSS Score
Published: May 27, 2026 at 08:20 PM UTC
Updated: October 25, 2026 at 11:10 PM UTC
1 product affected across 1 vendorPam USB

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Severity
HIGH7.8
Exploit prediction
EPSS 0.2%
SSVC
PoC

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.

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

SSVCPoCNot automatableTotal impact

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

CVSS

7.8HIGHGitHub_M
Attack Vector
LOCAL
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-78

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