CVE-2026-71209 (GCVE-0-2026-71209)

Vulnerability from cvelistv5 – Published: 2026-08-05 06:59 – Updated: 2026-08-05 06:59
VLAI
Title
audiobookshelf: %2F Encoding Discrepancy Bypasses Cover/Image Auth Exemption Regex, Enabling Unauthenticated Path Traversal
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. Express's router decodes the :id route parameter before handler code runs, so a %2F-encoded '../' sequence in :id (e.g. ..%2f..%2f..%2ftmp%2fpwned) passes the literal-path auth-exemption check while resolving to a real path-traversal payload once decoded. CacheManager.handleCoverCache then joins this decoded value into a cache file path and streams the result before any database-backed ownership check. This bypasses the fix applied for CVE-2025-25205 (which anchored the exemption regex and switched it to req.path) and results in unauthenticated arbitrary file read of any file matching the pattern *_<width>[x<height>].<ext> that the service account can read.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CWE
Assigner
References
Impacted products
Vendor Product Version
advplyr audiobookshelf Affected: 2.19.1 , ≤ 2.35.1 (custom)
Create a notification for this product.
Credits
Sarvar Omonov
Show details on NVD website
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unknown",
          "product": "audiobookshelf",
          "programFiles": [
            "server/routers/Auth.js",
            "server/managers/CacheManager.js"
          ],
          "vendor": "advplyr",
          "versions": [
            {
              "lessThanOrEqual": "2.35.1",
              "status": "affected",
              "version": "2.19.1",
              "versionType": "custom"
            }
          ]
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "Sarvar Omonov"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "audiobookshelf\u0027s 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. Express\u0027s router decodes the :id route parameter before handler code runs, so a %2F-encoded \u0027../\u0027 sequence in :id (e.g. ..%2f..%2f..%2ftmp%2fpwned) passes the literal-path auth-exemption check while resolving to a real path-traversal payload once decoded. CacheManager.handleCoverCache then joins this decoded value into a cache file path and streams the result before any database-backed ownership check. This bypasses the fix applied for CVE-2025-25205 (which anchored the exemption regex and switched it to req.path) and results in unauthenticated arbitrary file read of any file matching the pattern *_\u003cwidth\u003e[x\u003cheight\u003e].\u003cext\u003e that the service account can read."
        }
      ],
      "metrics": [
        {
          "other": {
            "content": {
              "value": "HIGH"
            },
            "type": "CVSS_3.1_severity"
          }
        },
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-22",
              "description": "CWE-22 Path Traversal",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T06:59:16.579Z",
        "orgId": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
        "shortName": "TuranSec"
      },
      "references": [
        {
          "url": "https://github.com/advplyr/audiobookshelf/security/advisories/GHSA-pg8v-5jcv-wrvw"
        },
        {
          "url": "https://github.com/advplyr/audiobookshelf"
        }
      ],
      "title": "audiobookshelf: %2F Encoding Discrepancy Bypasses Cover/Image Auth Exemption Regex, Enabling Unauthenticated Path Traversal"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c",
    "assignerShortName": "TuranSec",
    "cveId": "CVE-2026-71209",
    "datePublished": "2026-08-05T06:59:16.579Z",
    "dateReserved": "2026-08-05T06:56:15.799Z",
    "dateUpdated": "2026-08-05T06:59:16.579Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}



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