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TI-2026-31091 Aliases CVE-2026-42885

Audiobookshelf: Path prefix bypass in filesystem existence check leaks out-of-scope file existence

Priority MEDIUM 53CWE-22Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Information disclosure
Confidentiality · integrity · availability
Low · None · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-22 and the CVSS impact.

Summary

Audiobookshelf is a self-hosted audiobook and podcast server. Prior to 2.32.2, the POST /api/filesystem/pathexists endpoint uses String.startsWith() to validate that a resolved file path is within a library folder. This check fails for sibling directories whose names share a common prefix (e.g., /audiobooks vs /audiobooks-private), allowing authenticated users with upload permission to probe file existence outside their authorized library folder boundaries. This vulnerability is fixed in 2.32.2.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00282 20th percentileScored 2026-11-07
Fix Fixed audiobookshelf (advplyr): 2.33.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
advplyraudiobookshelfbefore 2.33.22.33.2Patch availableCNA
  • audiobookshelf Vendoradvplyr Affected before 2.33.2 Fixed in 2.33.2 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:audiobookshelf:audiobookshelf:*:*:*:*:*:*:*:*——advplyr
  • cpe:2.3:a:audiobookshelf:audiobookshelf:*:*:*:*:*:*:*:* Versions — — ·advplyr

Remediation

  • Fix · CNA audiobookshelf (advplyr) Fixed in 2.33.2

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-42885

References

Other 1

  • TI-2025-18874 Remote Authentication-Bypass can lead to server crash or limited information disclosure due to faulty pattern matching CVSS 3.1HIGH 8.2
  • TI-2025-35683 Audiobookshelf vulnerable to OIDC token exfiltration and account takeover CVSS 3.1HIGH 8.8
  • TI-2026-49884 Path traversal in advplyr audiobookshelf CVSS 3.1HIGH 7.5
  • TI-2025-29079 Audiobookshelf Vulnerable to Cross-Site-Scripting Reflected via POST Request in /api/upload CVSS 4.0MEDIUM 6.9
  • TI-2023-25761 Audiobookshelf Server-Side Request Forgery and Arbitrary File Read Vulnerability CVSS 3.1HIGH 8.1
  • TI-2026-31089 Audiobookshelf: Cross-library file exfiltration via unscoped bulk download endpoint CVSS 3.1MEDIUM 6.5
See all 19 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences