{"id":"GHSA-4v9q-p283-qc2m","summary":"Grav: Unauthenticated Path Traversal via Missing Directory-Boundary Check in `plugin-asset-map.php` Static Asset Server (`index.php`)","details":"**Verified against:** `getgrav/grav` devel branch, `GRAV_VERSION = \"2.0.15\"`, file `index.php\n\n## Title\nUnauthenticated Path Traversal via Missing Directory-Boundary Check in `plugin-asset-map.php` Static Asset Server (`index.php`)\n\n## Product / Affected Versions\n- Product: `getgrav/grav`\n- File: `index.php` (top-level front controller, runs before Grav itself boots)\n- Confirmed present in: devel branch, 2.0.15\n- **Precondition:** requires `user/config/plugin-asset-map.php` to exist and contain at least one route-prefix mapping ,this is an opt-in mechanism (per the code comment: \"Fast static asset serving for plugins that bundle SPA apps\"). No core mechanism generates this file automatically; it's created by a plugin that opts into this fast-path. **Not reachable on a stock Grav install with no such plugin.** Where reachable, it requires zero authentication.\n\n## CWE\nCWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') , specific mechanism: a path-prefix containment check performed with plain string comparison (`str_starts_with`) instead of a directory-boundary-aware comparison, allowing escape into any sibling path whose name happens to extend the base directory's name as a string.\n\n## Description\n\n`index.php` implements a fast-path static file server that runs *before* Grav's own routing/security stack, gated on the presence of an asset-map file:\n\n```php\n$assetMapFile = __DIR__ . '/user/config/plugin-asset-map.php';\nif (is_file($assetMapFile)) {\n    $assetMap = require $assetMapFile;\n    foreach ($assetMap as $routePrefix =\u003e $diskPath) {\n        if (str_starts_with($path, $routePrefix)) {\n            $relPath = substr($path, strlen($routePrefix));\n            $filePath = __DIR__ . '/' . ltrim($diskPath, '/') . $relPath;\n            $realFile = realpath($filePath);\n            $realBase = realpath(__DIR__ . '/' . ltrim($diskPath, '/'));\n            if ($realFile && $realBase && str_starts_with($realFile, $realBase) && is_file($realFile)) {\n                // ... serves $realFile directly, with Content-Type inferred from extension\n                readfile($realFile);\n                exit;\n            }\n        }\n    }\n}\n```\n\n`realpath()` correctly resolves `..` sequences, so a naive `../../etc/passwd`-style traversal that leaves the filesystem entirely is blocked (it wouldn't share the `$realBase` string prefix). **But the containment check itself, `str_starts_with($realFile, $realBase)`, has no directory-boundary awareness** it's a plain string-prefix test, not \"is `$realFile` inside the `$realBase` directory.\" Any resolved path whose string representation merely *begins with* the same characters as `$realBase` passes, including sibling directories that extend the base directory's name (`assets` → `assets-secret`, `assets.bak`, `assets_old`, `assets2`, etc.) a very common real-world directory-naming pattern (backup dirs, versioned dirs, disabled/legacy dirs sitting alongside the active one).\n\n## Live Proof of Concept\n\n**Setup:** the exact code block above, extracted verbatim from `index.php`, executed with PHP 8.3.6 against a realistic directory layout (a plugin's active `assets/` dir sitting next to an unrelated `assets-secret/` dir containing a fake secret):\n\n```\nuser/plugins/myplugin/assets/app.js            \u003c- intended, public\nuser/plugins/myplugin/assets-secret/config.php \u003c- NOT intended to be served\nuser/config/plugin-asset-map.php:\n    return ['/myplugin-assets' =\u003e 'user/plugins/myplugin/assets'];\n```\n\n**Legitimate request** (`/myplugin-assets/app.js`):\n```\nrealFile: '/home/claude/grav-poc/user/plugins/myplugin/assets/app.js'\nrealBase: '/home/claude/grav-poc/user/plugins/myplugin/assets'\n\u003e\u003e\u003e WOULD SERVE FILE \u003c\u003c\u003c\n\u003e\u003e\u003e Content: public asset content\n```\n\n**Traversal request** (`/myplugin-assets/../assets-secret/config.php`):\n```\nrealFile: '/home/claude/grav-poc/user/plugins/myplugin/assets-secret/config.php'\nrealBase: '/home/claude/grav-poc/user/plugins/myplugin/assets'\n\u003e\u003e\u003e WOULD SERVE FILE \u003c\u003c\u003c\n\u003e\u003e\u003e Content: SECRET_API_KEY=sk_live_totally_secret_12345\n```\n\n`str_starts_with('.../assets-secret/config.php', '.../assets')` evaluates `true` because `assets-secret` literally begins with the characters `assets` there is no separator-boundary check (e.g. requiring `$realBase . '/'` as the actual prefix) to prevent this.\n\n## Trust-boundary framing (per Grav's own SECURITY.md)\nThis code path requires **no Grav account** , it runs before Grav even initializes, directly off the raw request path. Per Grav's own stated criteria: *\"An unauthenticated attacker can achieve RCE, exfiltrate site data, or gain admin-equivalent control. No Grav account required\"* → this matches the **CRITICAL** bar exactly, for any deployment where the `plugin-asset-map.php` mechanism is in active use.\n\n## Suggested Fix\nAppend a trailing directory separator before the prefix comparison, or use a proper containment check:\n```php\nif ($realFile && $realBase && (\n    $realFile === $realBase ||\n    str_starts_with($realFile, $realBase . DIRECTORY_SEPARATOR)\n) && is_file($realFile)) {\n```\nThis is the standard fix for this exact bug class\n, ensuring the matched prefix ends exactly at a directory boundary, not partway through a longer sibling name.","aliases":["CVE-2026-74907"],"modified":"2026-09-17T21:00:05.790152292Z","published":"2026-09-17T20:43:16Z","database_specific":{"github_reviewed_at":"2026-09-17T20:43:16Z","nvd_published_at":null,"cwe_ids":["CWE-22"],"severity":"HIGH","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/getgrav/grav/security/advisories/GHSA-4v9q-p283-qc2m"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-74907"},{"type":"PACKAGE","url":"https://github.com/getgrav/grav"},{"type":"WEB","url":"https://www.vulncheck.com/advisories/grav-before-path-traversal-via-plugin-asset-map-php"}],"affected":[{"package":{"name":"getgrav/grav","ecosystem":"Packagist","purl":"pkg:composer/getgrav/grav"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.15"}]}],"versions":["0.8.0","0.9.0","0.9.1","0.9.10","0.9.11","0.9.12","0.9.13","0.9.14","0.9.15","0.9.16","0.9.17","0.9.18","0.9.19","0.9.2","0.9.20","0.9.21","0.9.22","0.9.23","0.9.24","0.9.25","0.9.26","0.9.27","0.9.28","0.9.29","0.9.3","0.9.30","0.9.31","0.9.32","0.9.33","0.9.34","0.9.35","0.9.36","0.9.37","0.9.38","0.9.39","0.9.4","0.9.40","0.9.41","0.9.42","0.9.43","0.9.44","0.9.45","0.9.5","0.9.6","0.9.7","0.9.8","0.9.9","1.0.0","1.0.0-rc.1","1.0.0-rc.2","1.0.0-rc.3","1.0.0-rc.4","1.0.0-rc.5","1.0.0-rc.6","1.0.1","1.0.10","1.0.2","1.0.3","1.0.4","1.0.5","1.0.6","1.0.7","1.0.8","1.0.9","1.1.0","1.1.0-beta.1","1.1.0-beta.2","1.1.0-beta.3","1.1.0-beta.4","1.1.0-beta.5","1.1.0-rc.1","1.1.0-rc.2","1.1.0-rc.3","1.1.1","1.1.10","1.1.11","1.1.12","1.1.13","1.1.14","1.1.15","1.1.16","1.1.17","1.1.2","1.1.3","1.1.4","1.1.5","1.1.6","1.1.7","1.1.8","1.1.9","1.1.9-rc.1","1.1.9-rc.2","1.1.9-rc.3","1.2.0","1.2.0-rc.1","1.2.0-rc.2","1.2.0-rc.3","1.2.1","1.2.2","1.2.3","1.2.4","1.3.0","1.3.0-rc.1","1.3.0-rc.2","1.3.0-rc.3","1.3.0-rc.4","1.3.0-rc.5","1.3.1","1.3.10","1.3.2","1.3.3","1.3.4","1.3.5","1.3.6","1.3.7","1.3.8","1.3.9","1.4.0","1.4.0-beta.1","1.4.0-beta.2","1.4.0-beta.3","1.4.0-rc.1","1.4.0-rc.2","1.4.1","1.4.2","1.4.3","1.4.4","1.4.5","1.4.6","1.4.7","1.4.8","1.5.0","1.5.0-beta.1","1.5.0-beta.2","1.5.0-rc.1","1.5.1","1.5.10","1.5.2","1.5.3","1.5.4","1.5.5","1.5.6","1.5.7","1.5.8","1.5.9","1.6.0","1.6.0-beta.1","1.6.0-beta.2","1.6.0-beta.3","1.6.0-beta.4","1.6.0-beta.5","1.6.0-beta.6","1.6.0-beta.7","1.6.0-beta.8","1.6.0-rc.1","1.6.0-rc.2","1.6.0-rc.3","1.6.0-rc.4","1.6.1","1.6.10","1.6.11","1.6.12","1.6.13","1.6.14","1.6.15","1.6.16","1.6.17","1.6.18","1.6.19","1.6.2","1.6.20","1.6.21","1.6.22","1.6.23","1.6.24","1.6.25","1.6.26","1.6.27","1.6.28","1.6.29","1.6.3","1.6.30","1.6.31","1.6.4","1.6.5","1.6.6","1.6.7","1.6.8","1.6.9","1.7.0","1.7.0-beta.1","1.7.0-beta.10","1.7.0-beta.2","1.7.0-beta.3","1.7.0-beta.4","1.7.0-beta.5","1.7.0-beta.6","1.7.0-beta.7","1.7.0-beta.8","1.7.0-beta.9","1.7.0-rc.1","1.7.0-rc.10","1.7.0-rc.11","1.7.0-rc.12","1.7.0-rc.13","1.7.0-rc.14","1.7.0-rc.15","1.7.0-rc.16","1.7.0-rc.17","1.7.0-rc.18","1.7.0-rc.19","1.7.0-rc.2","1.7.0-rc.20","1.7.0-rc.3","1.7.0-rc.4","1.7.0-rc.5","1.7.0-rc.6","1.7.0-rc.7","1.7.0-rc.8","1.7.0-rc.9","1.7.1","1.7.10","1.7.12","1.7.13","1.7.14","1.7.15","1.7.16","1.7.17","1.7.18","1.7.19","1.7.20","1.7.21","1.7.22","1.7.23","1.7.24","1.7.25","1.7.26","1.7.26.1","1.7.27","1.7.27.1","1.7.28","1.7.29","1.7.29.1","1.7.3","1.7.30","1.7.31","1.7.32","1.7.33","1.7.34","1.7.35","1.7.36","1.7.37","1.7.37.1","1.7.38","1.7.39","1.7.39.1","1.7.39.2","1.7.39.3","1.7.39.4","1.7.4","1.7.40","1.7.41","1.7.41.1","1.7.41.2","1.7.42","1.7.42.1","1.7.42.2","1.7.42.3","1.7.43","1.7.44","1.7.45","1.7.46","1.7.47","1.7.48","1.7.49","1.7.49.1","1.7.49.2","1.7.49.3","1.7.49.4","1.7.49.5","1.7.5","1.7.51","1.7.52","1.7.53","1.7.53.1","1.7.53.2","1.7.53.3","1.7.6","1.7.7","1.7.8","1.7.9","1.8.0-beta.1","1.8.0-beta.10","1.8.0-beta.11","1.8.0-beta.12","1.8.0-beta.13","1.8.0-beta.14","1.8.0-beta.15","1.8.0-beta.16","1.8.0-beta.17","1.8.0-beta.18","1.8.0-beta.19","1.8.0-beta.2","1.8.0-beta.20","1.8.0-beta.21","1.8.0-beta.22","1.8.0-beta.23","1.8.0-beta.24","1.8.0-beta.25","1.8.0-beta.26","1.8.0-beta.27","1.8.0-beta.28","1.8.0-beta.29","1.8.0-beta.3","1.8.0-beta.4","1.8.0-beta.5","1.8.0-beta.6","1.8.0-beta.7","1.8.0-beta.8","1.8.0-beta.9","2.0.0","2.0.0-beta.1","2.0.0-beta.2","2.0.0-beta.3","2.0.0-beta.4","2.0.0-rc.1","2.0.0-rc.10","2.0.0-rc.2","2.0.0-rc.3","2.0.0-rc.4","2.0.0-rc.5","2.0.0-rc.6","2.0.0-rc.7","2.0.0-rc.8","2.0.0-rc.9","2.0.1","2.0.10","2.0.11","2.0.12","2.0.13","2.0.14","2.0.2","2.0.3","2.0.4","2.0.5","2.0.6","2.0.7","2.0.8","2.0.9"],"database_specific":{"last_known_affected_version_range":"\u003c= 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