{"id":"CVE-2026-48983","aliases":["EUVD-2026-37936","GHSA-4j8q-67fq-3xc3"],"status":"published","title":"pam_usb: TOCTOU race condition in pad directory creation allows symlink substitution","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.","severity":{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00107,"percentile":0.01136,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-367"],"published":"2026-06-18T19:07:56Z","modified":"2026-10-28T11:16:26Z","products":[{"vendor":"mcdope","product":"pam_usb"}],"references":[{"url":"https://github.com/mcdope/pam_usb/security/advisories/GHSA-4j8q-67fq-3xc3","tags":["x_refsource_CONFIRM","advisory"]},{"url":"https://github.com/mcdope/pam_usb/releases/tag/0.9.2","tags":["x_refsource_MISC","web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48983.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48983","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-48983","title":"pam_usb: TOCTOU race condition in pad directory creation allows symlink substitution","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.","status":"published","published":"2026-06-18T19:07:56.198Z","modified":"2026-06-22T12:41:34.711Z","cvss":[{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L","level":"medium","assessor":"cna"}],"cwes":["CWE-367"],"updated_at":"2026-11-02T14:19:47.998488Z"}],"euvd":[{"id":"EUVD-2026-37936","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.","status":"published","published":"2026-06-18T19:07:56Z","modified":"2026-06-22T12:41:34Z","cvss":[{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L","level":"medium"}],"updated_at":"2026-11-02T18:20:35.26548Z"}],"nvd":[{"id":"CVE-2026-48983","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.","status":"published","published":"2026-06-18T20:16:14.657Z","modified":"2026-10-26T11:10:00.157Z","cvss":[{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L","level":"medium","assessor":"secondary"}],"cwes":["CWE-367"],"updated_at":"2026-11-02T14:12:24.912854Z"}],"osv":[{"id":"CVE-2026-48983","title":"pam_usb: TOCTOU race condition in pad directory creation allows symlink substitution","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.","status":"published","published":"2026-06-18T19:07:56.198Z","modified":"2026-10-28T11:16:26.562033033Z","cvss":[{"version":"3.1","score":5.8,"vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L","level":"medium"}],"cwes":["CWE-367"],"updated_at":"2026-11-02T15:45:07.060148Z"}]}}