CVE-2026-71209: audiobookshelf - %2F Encoding Discrepancy Bypasses Cover/Image Auth Exemption Regex, Enabling Unauthenticated Path Traversal

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.2% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-08-05 · updated 2026-10-24
Weakness: CWE-22

Description

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. CacheManager.handleCoverCache then joins this decoded value into a cache file path and streams the result before any database-backed ownership check.

Affected products

advplyr audiobookshelf: from 2.19.1 through 2.35.1

References

https://github.com/advplyr/audiobookshelf
https://github.com/advplyr/audiobookshelf/security/advisories/GHSA-pg8v-5jcv-wrvw
https://github.com/advplyr/audiobookshelf/security/advisories/GHSA-pg8v-5jcv-wrvw

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