Vulnerability in Mcdope Pam Usb
CVE-2026-48983
pam_usb provides hardware authentication for Linux using ordinary removable media. In versions prior to 0.9.2, a symlink race condition exists in per-device and per-user pad directory creation. pam_usb uses a check-then-act pattern: it calls lstat() to test for existence and then calls mkdir() separately to create the directory. A local attacker can win the race between these calls by replacing the target path with a symlink to a directory they control. If successful, one-time pad files may be written to an attacker-controlled location, potentially exposing future pad values before use or disrupting authentication. This issue has been fixed in version 0.9.2.
Vulnerability class: TOCTOU (Time-of-Check to Time-of-Use)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.8 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L.
EPSS exploit prediction
EPSS: 0.001 (1.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 1st percentile — 1.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: 0.000
Affected products
- Mcdope Pam Usb — versions < 0.9.2
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-48983?
- CVE-2026-48983 is a medium-severity vulnerability in Mcdope Pam Usb, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 5.8/10. Published 2026-06-18.
- How severe is CVE-2026-48983?
- Medium severity. CVSS v3 base score is 5.8 out of 10.