{"id":"CVE-2026-71209","summary":"audiobookshelf: %2F Encoding Discrepancy Bypasses Cover/Image Auth Exemption Regex, Enabling Unauthenticated Path Traversal","details":"audiobookshelf's authentication-exemption check (server/routers/Auth.js) matches unauthenticated-allowed GET routes against req.path via a regex requiring a literal /items/:id/cover or /authors/:id/image shape, where req.path retains %2F sequences URL-encoded. Express's router decodes the :id route parameter before handler code runs, so a %2F-encoded '../' sequence in :id (e.g. ..%2f..%2f..%2ftmp%2fpwned) passes the literal-path auth-exemption check while resolving to a real path-traversal payload once decoded. CacheManager.handleCoverCache then joins this decoded value into a cache file path and streams the result before any database-backed ownership check. This bypasses the fix applied for CVE-2025-25205 (which anchored the exemption regex and switched it to req.path) and results in unauthenticated arbitrary file read of any file matching the pattern *_\u003cwidth\u003e[x\u003cheight\u003e].\u003cext\u003e that the service account can read.","aliases":["CVE-2025-25205","GHSA-pg8v-5jcv-wrvw"],"modified":"2026-08-07T11:56:15.237604250Z","published":"2026-08-05T06:59:16.579Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/71xxx/CVE-2026-71209.json","cna_assigner":"TuranSec","cwe_ids":["CWE-22"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/71xxx/CVE-2026-71209.json"},{"type":"ADVISORY","url":"https://github.com/advplyr/audiobookshelf/security/advisories/GHSA-pg8v-5jcv-wrvw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-71209"},{"type":"PACKAGE","url":"https://github.com/advplyr/audiobookshelf"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/advplyr/audiobookshelf","events":[{"introduced":"725192fbc0f5b289bc70a4eed451710359464ca6"},{"last_affected":"aacdcc47ec0b6fa778b84627c79deb7ee0cecd70"}],"database_specific":{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"2.19.1"},{"last_affected":"2.35.1"}]}}],"versions":["v2.35.1","v2.35.0","v2.34.0","v2.33.2","v2.33.1","v2.33.0","v2.32.1","v2.32.0","v2.31.0","v2.30.0","v2.29.0","v2.28.0","v2.27.0","v2.26.3","v2.26.2","v2.26.1","v2.26.0","v2.25.1","v2.25.0","v2.24.0","v2.23.0","v2.22.0","v2.21.0","v2.20.0","v2.19.5","v2.19.4","v2.19.3","v2.19.2","v2.19.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-71209.json"}}],"schema_version":"1.8.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"}]}