Path Traversal in Audiobookshelf (CVE-2026-42885)
Summary
Path traversal in Audiobookshelf (CVE-2026-42885). Risk of unauthorized operations or information disclosure. Exploitable via POST /api/filesystem/pathexists. Mitigation: upgrade to 2.32.2 or later.
Original description
The description as published by the source.
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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-42885 has been found in Audiobookshelf.
Attackers can target a specific entry point like POST /api/filesystem/pathexists over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 4.3/10.
What to do: upgrade Audiobookshelf to 2.32.2 or later.
If unsure, ask your IT team or search "Audiobookshelf CVE-2026-42885" on the vendor's site.
CVE-2026-42885 (Audiobookshelf) — CWE-22 / CVSS v3 4.3
Attack vector: remote (network-reachable) / no user interaction
Attack surface: POST /api/filesystem/pathexists
Patched: 2.32.2 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Path traversal (CWE-22) exists in Audiobookshelf. Attackers reach the vulnerable code path via POST /api/filesystem/pathexists.
Check the vendor advisory for the affected versions of Audiobookshelf. Attack surface: POST /api/filesystem/pathexists.
Severity: Medium (CVSS 4.3/10). Risk of unauthorized operations or information disclosure.
Update to 2.32.2.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual POST /api/filesystem/pathexists requests with malformed payloads or SQL meta-characters. Run grep -r 'Audiobookshelf' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'Audiobookshelf' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
Audiobookshelfを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'POST /api/filesystem/pathexists' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /api/filesystem/pathexistsへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade Audiobookshelf to 2.32.2ステージング環境で 2.32.2 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against POST /api/filesystem/pathexists on staging to confirm patch closes the vectorパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。
References
- advisory github.com
- advisory github.com
- advisory nvd.nist.gov