CVE-2026-48066CWE-362CWE-476

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

Medium · published May 27, 2026

CVSS v3.1
5.7
EPSS
0%
Percentile
3.1
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.7 · MEDIUM
Vector
CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
CVSS v4.0
Not supplied
EPSS
0.00141 · 3.1th percentile
Weaknesses
CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition'); CWE-476 · NULL Pointer Dereference
Published
2026-05-27T19:57Z
EPSS history
Timeline
  • 27 MAY 19:57Z
    pam_usb: Thread-unsafe static pointer in log.c causes data race under concurrent PAM authentication
    cvelistv5