{"id":"CVE-2026-48983","summary":"pam_usb: TOCTOU race condition in pad directory creation allows symlink substitution","details":"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.","aliases":["GHSA-4j8q-67fq-3xc3"],"modified":"2026-07-08T08:12:35.088474544Z","published":"2026-06-18T19:07:56.198Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-367"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48983.json"},"references":[{"type":"WEB","url":"https://github.com/mcdope/pam_usb/releases/tag/0.9.2"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48983.json"},{"type":"ADVISORY","url":"https://github.com/mcdope/pam_usb/security/advisories/GHSA-4j8q-67fq-3xc3"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48983"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/mcdope/pam_usb","events":[{"introduced":"0"},{"fixed":"d4083e266b7e18e41e58b3392b5856941a3b5b1c"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"0.9.2"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["0.9.1","0.9.0","0.8.7","0.8.4","0.8.3","v0.8.0","0.7.3","0.7.2","0.7.1","v0.7.0","0.5.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-48983.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:L"}]}