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Fencer Vulns
high 7.5

CVE-2026-71209 json

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

published 2026-08-05 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-53206

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.2%
EPSS 2.2% chance of exploitation in 30 days, percentile 83%
public exploits
0
none known, plus a Nuclei check

Summary

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.

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

2.25% chance of exploitation in the next 30 days, higher than 83% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • Nuclei template Audiobookshelf - Authentication Bypass nuclei detection template
  • github.com https://github.com/advplyr/audiobookshelf/security/advisories/GHSA-pg8v-5jcv-wrvw referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products

  • advplyr audiobookshelf

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.