{"id":"GHSA-jq29-c7v8-rg55","summary":"Grav: Path Traversal in MediaUploadTrait::deleteFile() Allows Arbitrary File Deletion","details":"# Path Traversal in MediaUploadTrait::deleteFile() Allows Arbitrary File Deletion\n\n## Summary\n\nA path traversal vulnerability in `MediaUploadTrait::deleteFile()` allows an authenticated user with media management permissions to delete arbitrary files on the server. The method validates only the basename portion of the filename using `Utils::checkFilename()`, while the directory path (which may contain `../` sequences) is preserved and passed unvalidated to `unlink()`. This enables directory escape from the intended media storage path.\n\n## Severity\n\n**High (8.1)** - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H\n\n## CWE\n\nCWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')\n\n## Details\n\nIn `system/src/Grav/Common/Media/Traits/MediaUploadTrait.php`, the `deleteFile()` method (lines 332-365) performs filename validation only on the basename, not the full path:\n\n```php\npublic function deleteFile(string $filename, ?array $settings = null): void\n{\n    $settings = $this-\u003egetUploadSettings($settings);\n    $filesystem = Filesystem::getInstance(false);\n\n    // Line 339-340: Only the BASENAME is validated\n    $basename = $filesystem-\u003ebasename($filename);  // e.g. \"evil.jpg\" from \"../../evil.jpg\"\n    if (!Utils::checkFilename($basename)) {         // passes - no traversal in basename\n        throw new RuntimeException(/* ... */);\n    }\n\n    $path = $settings['destination'] ?? $this-\u003egetPath();\n    // ...\n\n    // Line 353: Full pathname (with traversal) is preserved\n    $pathname = $filesystem-\u003epathname($filename);   // \"../../\"\n\n    // Line 356-357: Traversal path reconstructed\n    [$base, $ext,,] = $this-\u003egetFileParts($basename);\n    $name = \"{$pathname}{$base}.{$ext}\";            // \"../../evil.jpg\"\n\n    // Line 360: Passed to doRemove()\n    $this-\u003edoRemove($name, $path);\n}\n```\n\n`doRemove()` (line 521-582) then calls:\n\n```php\n// Line 538\nunlink(\"{$folder}/{$filename}\");\n// e.g. unlink(\"/var/www/grav/user/pages/mypage/../../config/system.yaml\")\n```\n\n`Utils::checkFilename()` (lines 1022-1044) properly checks for `/`, `\\`, and `..`, but it is applied to `$filesystem-\u003ebasename($filename)` (the last path component only), so traversal sequences in the directory portion are never validated.\n\n### Data flow from user input\n\nThe vulnerability is reachable through the Flex media handling pipeline:\n\n1. `FlexMediaTrait::setUpdatedMedia()` (line 386) iterates form flash data where `$filename` is the array key - user-controlled\n2. For file deletions (`$file` is null, line 396), NO upload validation is performed (the `checkUploadedFile()` call at line 401 only executes when `$file` is truthy)\n3. The raw filename is stored in `$this-\u003e_uploads` at line 414\n4. `saveUpdatedMedia()` (line 499) calls `$media-\u003edeleteFile($filename, $settings)` with the unsanitized filename\n\n### Sibling: renameFile()\n\nThe same pattern exists in `renameFile()` (lines 374-405) which has even weaker validation - it performs NO `checkFilename()` call at all. While `renameFile()` currently has no callers in the core codebase, it is part of the public `MediaUploadInterface` and should be fixed as defense-in-depth.\n\n## Proof of Concept\n\n**Environment**: Grav CMS 2.0.16 with admin plugin\n\nThe attack requires an authenticated admin user with page/media editing permissions (not super-admin).\n\n1. Create a target file:\n```bash\necho \"DELETE_ME\" \u003e /var/www/grav/user/data/target.txt\n```\n\n2. Submit a Flex object form (e.g. page edit) with a crafted media deletion where the filename key contains path traversal:\n\n```\nPOST /admin/pages/mypage/task:save\nContent-Type: multipart/form-data\n\n# The form flash data includes a media deletion entry with key:\n# \"../../data/target.txt\" -\u003e null (deletion marker)\n```\n\n3. When `saveUpdatedMedia()` processes the deletion queue:\n   - `$filename` = `../../data/target.txt`\n   - `deleteFile(\"../../data/target.txt\")` is called\n   - `$basename` = `target.txt` (passes `checkFilename()`)\n   - `$pathname` = `../../data/`\n   - `$name` = `../../data/target.txt`\n   - `doRemove()` calls `unlink(\"/var/www/grav/user/pages/mypage/../../data/target.txt\")`\n   - Which resolves to `unlink(\"/var/www/grav/user/data/target.txt\")`\n\n4. The file is deleted outside the intended media directory.\n\n### Impact\n\nAn authenticated user with media management permissions can:\n- Delete configuration files (`user/config/system.yaml`, `user/config/security.yaml`)\n- Delete other pages' content files\n- Delete authentication-related files (user account YAML files)\n- Cause denial of service by removing critical application files\n- Potentially escalate privileges by removing security configuration\n\n## Suggested Fix\n\nApply `Utils::checkFilename()` to the full `$filename` parameter before decomposing it, or reject any filename containing directory separators or `..` sequences:\n\n```php\npublic function deleteFile(string $filename, ?array $settings = null): void\n{\n    $settings = $this-\u003egetUploadSettings($settings);\n    $filesystem = Filesystem::getInstance(false);\n\n    // Validate the FULL filename, not just the basename\n    if (!Utils::checkFilename($filename)) {\n        throw new RuntimeException(/* ... */);\n    }\n\n    // ... rest unchanged\n}\n```\n\nThe same fix should be applied to `renameFile()` for both `$from` and `$to` parameters.\n\n## References\n\n- Vulnerable file: `system/src/Grav/Common/Media/Traits/MediaUploadTrait.php` lines 332-365, 521-582\n- Caller: `system/src/Grav/Framework/Flex/Traits/FlexMediaTrait.php` lines 386-414, 490-499\n- Sibling: `system/src/Grav/Common/Media/Traits/MediaUploadTrait.php` lines 374-405 (renameFile)\n- Related GHSA: GHSA-g6j3-8jv9-ch5f (path traversal in PagesController::batchCopy - different file, same bug class)\n\n## Disclosure\n\nThis vulnerability was discovered using AI-assisted security research tools.","aliases":["CVE-2026-72695"],"modified":"2026-09-17T20:45:05.940427846Z","published":"2026-09-17T20:34:05Z","database_specific":{"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-09-17T20:34:05Z","nvd_published_at":null,"cwe_ids":["CWE-22"]},"references":[{"type":"WEB","url":"https://github.com/getgrav/grav/security/advisories/GHSA-jq29-c7v8-rg55"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-72695"},{"type":"PACKAGE","url":"https://github.com/getgrav/grav"},{"type":"WEB","url":"https://www.vulncheck.com/advisories/grav-before-path-traversal-via-mediauploadtrait-deletefile"}],"affected":[{"package":{"name":"getgrav/grav","ecosystem":"Packagist","purl":"pkg:composer/getgrav/grav"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.16"}]}],"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","2.0.15","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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