CVE-2026-48066

pam_usb: Thread-unsafe static pointer in log.c causes data race under concurrent PAM authentication

MEDIUM
5.7
CVSS Score
Published: May 27, 2026 at 07:57 PM UTC
Updated: October 26, 2026 at 11:10 AM UTC
1 product affected across 1 vendorPam USB

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Severity
MEDIUM5.7
Exploit prediction
EPSS 0.1%
SSVC
No known exploit

Description

pam_usb provides hardware authentication for Linux using ordinary removable media. Prior to 0.9.1, src/log.c contains a process-wide static pointer that is written on every PAM invocation with the address of a stack-local variable. This violates the PAM re-entrancy requirement and creates a data race when the PAM stack is invoked concurrently from multiple threads. This vulnerability is fixed in 0.9.1.

Affected

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

v < 0.9.1
Affected range stops below 0.9.1, 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 (3)

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

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

CVSS

5.7MEDIUMGitHub_M
Attack Vector
LOCAL
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
HIGH
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-362CWE-476

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