CVE-2026-48983
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.
Does this matter?
Lower severity and a low EPSS score (0.11%). Track it; it rarely justifies an emergency change on its own.
Description
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.
- CVSS 3.1
- 5.8 MEDIUMCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L
- EPSS
- 0.11% probability · 1th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-367
- Source
- security-advisories@github.com
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.