{"id":"CVE-2026-21857","aliases":["EUVD-2026-0817","GHSA-824x-88xg-cwrv"],"status":"published","title":"Redaxo has Path Traversal in Backup Addon Leading to Arbitrary File Read","description":"REDAXO is a PHP-based content management system. Prior to version 5.20.2, authenticated users with backup permissions can read arbitrary files within the webroot via path traversal in the Backup addon's file export functionality. The Backup addon does not validate the `EXPDIR` POST parameter against the UI-generated allowlist of permitted directories. An attacker can supply relative paths containing `../` sequences (or even absolute paths inside the document root) to include any readable file in the generated `.tar.gz` archive. Version 5.20.2 fixes this issue.","severity":{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00535,"percentile":0.45617,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":true,"fix_available":true},"cwes":["CWE-22","CWE-24"],"published":"2026-01-05T20:02:58Z","modified":"2026-10-28T02:30:27Z","exploits":[{"source":"pocgithub","id":"lukasz-rybak/CVE-2026-21857","title":"lukasz-rybak/CVE-2026-21857","date":"2026-04-11","url":"https://github.com/lukasz-rybak/CVE-2026-21857"}],"fixes":[{"ecosystem":"Packagist","package":"redaxo/source","fixed_in":["5.20.2"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Packagist","package":"redaxo/source","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"5.20.1"},{"fixed":"5.20.2"}]}]},{"source":"osv","ecosystem":"Packagist","package":"redaxo/source","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.20.2"}]}],"versions":["5.10.0","5.10.0-beta1","5.10.0-beta2","5.10.1","5.11.0","5.11.0-beta1","5.11.1","5.11.2","5.12.0","5.12.0-beta1","5.12.0-beta2","5.12.0-beta3","5.12.1","5.13.0","5.13.0-beta1","5.13.0-beta2","5.13.1","5.13.2","5.13.3","5.14.0","5.14.0-beta1","5.14.0-beta2","5.14.1","5.14.2","5.14.3","5.15.0","5.15.0-beta1","5.15.1","5.16.0","5.16.0-beta1","5.16.1","5.17.0","5.17.1","5.18.0","5.18.1","5.18.2","5.18.3","5.19.0","5.20.0","5.20.1"]}],"products":[{"vendor":"redaxo","product":"redaxo"}],"references":[{"url":"https://github.com/redaxo/redaxo/security/advisories/GHSA-824x-88xg-cwrv","tags":["x_refsource_CONFIRM","exploit","Exploit","Vendor Advisory","advisory","web"]},{"url":"https://github.com/redaxo/redaxo/releases/tag/5.20.2","tags":["x_refsource_MISC","Release Notes","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-21857","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-824x-88xg-cwrv"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/21xxx/CVE-2026-21857.json","tags":["advisory"]},{"url":"https://github.com/redaxo/redaxo","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-21857","title":"Redaxo has Path Traversal in Backup Addon Leading to Arbitrary File Read","description":"REDAXO is a PHP-based content management system. Prior to version 5.20.2, authenticated users with backup permissions can read arbitrary files within the webroot via path traversal in the Backup addon's file export functionality. The Backup addon does not validate the `EXPDIR` POST parameter against the UI-generated allowlist of permitted directories. An attacker can supply relative paths containing `../` sequences (or even absolute paths inside the document root) to include any readable file in the generated `.tar.gz` archive. Version 5.20.2 fixes this issue.","status":"published","published":"2026-01-07T22:32:15.859Z","modified":"2026-01-08T18:17:35.89Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:N","level":"high","assessor":"cna"}],"cwes":["CWE-24","CWE-22"],"updated_at":"2026-11-02T13:41:42.05254Z"}],"euvd":[{"id":"EUVD-2026-0817","description":"REDAXO is a PHP-based content management system. Prior to version 5.20.2, authenticated users with backup permissions can read arbitrary files within the webroot via path traversal in the Backup addon's file export functionality. The Backup addon does not validate the `EXPDIR` POST parameter against the UI-generated allowlist of permitted directories. An attacker can supply relative paths containing `../` sequences (or even absolute paths inside the document root) to include any readable file in the generated `.tar.gz` archive. Version 5.20.2 fixes this issue.","status":"published","published":"2026-01-07T22:32:15Z","modified":"2026-01-08T18:17:35Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:N","level":"high"}],"updated_at":"2026-11-02T19:48:54.487856Z"}],"ghsa":[{"id":"GHSA-824x-88xg-cwrv","title":"Redaxo has Path Traversal in Backup Addon Leading to Arbitrary File Read","description":"### Summary\nAuthenticated users with backup permissions can read arbitrary files within the webroot via path traversal in the Backup addon's file export functionality.\n\u003cimg width=\"664\" height=\"899\" alt=\"image\" src=\"https://github.com/user-attachments/assets/fd1ca69e-b275-4daf-9a62-621cde6525f5\" /\u003e\n\u003cimg width=\"2358\" height=\"445\" alt=\"image\" src=\"https://github.com/user-attachments/assets/fad81152-9e1b-413e-9823-09540a23e2fb\" /\u003e\n\n\n### Details\nThe Backup addon does not validate the `EXPDIR` POST parameter against the UI-generated allowlist of permitted directories.  \nAn attacker can supply relative paths containing `../` sequences (or even absolute paths inside the document root) to include any readable file in the generated `.tar.gz` archive.\n\nVulnerable code:\n- `redaxo/src/addons/backup/pages/export.php` (lines 72-76) – directly uses `$_POST['EXPDIR']`\n- `redaxo/src/addons/backup/lib/backup.php` (lines ~413 \u0026 ~427) – concatenates unsanitized user input with base path\n\nThis allows disclosure of sensitive files such as:\n- `redaxo/data/core/config.yml` → database credentials + password hashes of all backend users\n- `.env`, custom configuration files, logs, uploaded malicious files, etc.\n\n### Affected versions\n≤ 5.20.1 (confirmed working)\n\n### Patched versions\nNone (as of 2025-12-09)\n\n### PoC – Extracting database credentials and password hashes\n1. Log in as any user with Backup permission\n2. Go to Backup → Export → Files\n\n\u003cimg width=\"1240\" height=\"960\" alt=\"image\" src=\"https://github.com/user-attachments/assets/bc05ba18-9664-4be2-b637-4fec3a0f409a\" /\u003e\n\n3. Intercept the request with Burp Suite \n\n\u003cimg width=\"2184\" height=\"478\" alt=\"image\" src=\"https://github.com/user-attachments/assets/9fa754a1-2cd0-4d3d-a5cc-cfa34c8a1718\" /\u003e\n\n4. Change one `EXPDIR[]` value to `../../../../var/www/html/redaxo/data/core`\n\n\u003cimg width=\"978\" height=\"591\" alt=\"image\" src=\"https://github.com/user-attachments/assets/d15f5c7f-b72c-44cc-9be2-da8d3f26f124\" /\u003e\n\n5. Send request → download archive\n\u003cimg width=\"423\" height=\"131\" alt=\"image\" src=\"https://github.com/user-attachments/assets/db8a8bda-cdaf-4dea-812f-1e312da908e2\" /\u003e\n\n6. Extract and open `data/core/config.yml`\n\u003cimg width=\"859\" height=\"281\" alt=\"image\" src=\"https://github.com/user-attachments/assets/c8112ce1-5a1d-435f-953b-7eb4e711e042\" /\u003e\n\nResult: plaintext database password \n\u003cimg width=\"2534\" height=\"1198\" alt=\"image\" src=\"https://github.com/user-attachments/assets/218ae917-868a-437e-98b0-6471b82c0b10\" /\u003e\n\n### Impact\nFull compromise of the REDAXO installation:\n- Database takeover\n- Password hash extraction → offline cracking → admin access\n- When combined with other vulnerabilities → RCE\n\nCVSS 4.0 vector \u0026 score below.\n\n### Credits\nDiscovered by: Łukasz Rybak","status":"published","published":"2026-01-05T20:02:58Z","modified":"2026-01-08T20:07:43Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:N","level":"high"}],"cwes":["CWE-22","CWE-24"],"updated_at":"2026-11-02T14:39:16.156387Z"}],"nvd":[{"id":"CVE-2026-21857","description":"REDAXO is a PHP-based content management system. Prior to version 5.20.2, authenticated users with backup permissions can read arbitrary files within the webroot via path traversal in the Backup addon's file export functionality. The Backup addon does not validate the `EXPDIR` POST parameter against the UI-generated allowlist of permitted directories. An attacker can supply relative paths containing `../` sequences (or even absolute paths inside the document root) to include any readable file in the generated `.tar.gz` archive. Version 5.20.2 fixes this issue.","status":"published","published":"2026-01-07T23:15:50.83Z","modified":"2026-06-17T10:19:02.403Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"},{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-22","CWE-24"],"updated_at":"2026-11-02T14:12:03.683495Z"}],"osv":[{"id":"CVE-2026-21857","title":"Redaxo has Path Traversal in Backup Addon Leading to Arbitrary File Read","description":"REDAXO is a PHP-based content management system. Prior to version 5.20.2, authenticated users with backup permissions can read arbitrary files within the webroot via path traversal in the Backup addon's file export functionality. The Backup addon does not validate the `EXPDIR` POST parameter against the UI-generated allowlist of permitted directories. An attacker can supply relative paths containing `../` sequences (or even absolute paths inside the document root) to include any readable file in the generated `.tar.gz` archive. Version 5.20.2 fixes this issue.","status":"published","published":"2026-01-07T22:32:15.859Z","modified":"2026-10-28T02:30:27.273355613Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:N","level":"high"}],"cwes":["CWE-22","CWE-24"],"updated_at":"2026-11-02T15:44:58.42038Z"},{"id":"GHSA-824x-88xg-cwrv","title":"Redaxo has Path Traversal in Backup Addon Leading to Arbitrary File Read","description":"### Summary\nAuthenticated users with backup permissions can read arbitrary files within the webroot via path traversal in the Backup addon's file export functionality.\n\u003cimg width=\"664\" height=\"899\" alt=\"image\" src=\"https://github.com/user-attachments/assets/fd1ca69e-b275-4daf-9a62-621cde6525f5\" /\u003e\n\u003cimg width=\"2358\" height=\"445\" alt=\"image\" src=\"https://github.com/user-attachments/assets/fad81152-9e1b-413e-9823-09540a23e2fb\" /\u003e\n\n\n### Details\nThe Backup addon does not validate the `EXPDIR` POST parameter against the UI-generated allowlist of permitted directories.  \nAn attacker can supply relative paths containing `../` sequences (or even absolute paths inside the document root) to include any readable file in the generated `.tar.gz` archive.\n\nVulnerable code:\n- `redaxo/src/addons/backup/pages/export.php` (lines 72-76) – directly uses `$_POST['EXPDIR']`\n- `redaxo/src/addons/backup/lib/backup.php` (lines ~413 \u0026 ~427) – concatenates unsanitized user input with base path\n\nThis allows disclosure of sensitive files such as:\n- `redaxo/data/core/config.yml` → database credentials + password hashes of all backend users\n- `.env`, custom configuration files, logs, uploaded malicious files, etc.\n\n### Affected versions\n≤ 5.20.1 (confirmed working)\n\n### Patched versions\nNone (as of 2025-12-09)\n\n### PoC – Extracting database credentials and password hashes\n1. Log in as any user with Backup permission\n2. Go to Backup → Export → Files\n\n\u003cimg width=\"1240\" height=\"960\" alt=\"image\" src=\"https://github.com/user-attachments/assets/bc05ba18-9664-4be2-b637-4fec3a0f409a\" /\u003e\n\n3. Intercept the request with Burp Suite \n\n\u003cimg width=\"2184\" height=\"478\" alt=\"image\" src=\"https://github.com/user-attachments/assets/9fa754a1-2cd0-4d3d-a5cc-cfa34c8a1718\" /\u003e\n\n4. Change one `EXPDIR[]` value to `../../../../var/www/html/redaxo/data/core`\n\n\u003cimg width=\"978\" height=\"591\" alt=\"image\" src=\"https://github.com/user-attachments/assets/d15f5c7f-b72c-44cc-9be2-da8d3f26f124\" /\u003e\n\n5. Send request → download archive\n\u003cimg width=\"423\" height=\"131\" alt=\"image\" src=\"https://github.com/user-attachments/assets/db8a8bda-cdaf-4dea-812f-1e312da908e2\" /\u003e\n\n6. Extract and open `data/core/config.yml`\n\u003cimg width=\"859\" height=\"281\" alt=\"image\" src=\"https://github.com/user-attachments/assets/c8112ce1-5a1d-435f-953b-7eb4e711e042\" /\u003e\n\nResult: plaintext database password \n\u003cimg width=\"2534\" height=\"1198\" alt=\"image\" src=\"https://github.com/user-attachments/assets/218ae917-868a-437e-98b0-6471b82c0b10\" /\u003e\n\n### Impact\nFull compromise of the REDAXO installation:\n- Database takeover\n- Password hash extraction → offline cracking → admin access\n- When combined with other vulnerabilities → RCE\n\nCVSS 4.0 vector \u0026 score below.\n\n### Credits\nDiscovered by: Łukasz Rybak","status":"published","published":"2026-01-05T20:02:58Z","modified":"2026-02-03T03:16:15.825644Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:H/SI:H/SA:N","level":"high"}],"cwes":["CWE-22","CWE-24"],"updated_at":"2026-11-02T15:46:41.732368Z"}]}}