{"id":"CVE-2026-19418","aliases":["GHSA-68jx-f42c-7599"],"title":"TYPO3 CMS - Broken Access Control in Backend and Install Tool","summary":"TYPO3 CMS - Broken Access Control in Backend and Install Tool","severity":"high","cwe":["CWE-346","CWE-352"],"vendor":"typo3","product":"typo3/cms-backend","ecosystem":"composer","affected":["typo3/cms-backend >= 13.0.0, < 13.4.34","typo3/cms-core >= 14.0.0, < 14.3.6"],"patched":["typo3/cms-backend 13.4.34","typo3/cms-core 14.3.6"],"published":"2026-09-01","updated":"2026-09-01","source":"GHSA","sourceUrl":"https://github.com/advisories/GHSA-68jx-f42c-7599","references":[{"url":"https://github.com/TYPO3/typo3/security/advisories/GHSA-68jx-f42c-7599"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-19418"},{"url":"https://github.com/TYPO3/typo3/commit/4a75e862c589c85d795d7c65dcdc835f8f413efc"},{"url":"https://github.com/TYPO3/typo3/commit/a0e8ee06a40e959b9e7b06a4b1cb19d3a0d3dcf7"},{"url":"https://github.com/TYPO3/typo3/commit/ae0abd329d52285fe6e92804c3608820ad45e872"},{"url":"https://github.com/FriendsOfPHP/security-advisories/blob/master/typo3/cms-core/CVE-2026-19418.yaml"},{"url":"https://news.typo3.com/security/advisory/typo3-core-sa-2026-021"},{"url":"https://typo3.org/security/advisory/typo3-core-sa-2020-006"},{"url":"https://typo3.org/security/advisory/typo3-core-sa-2026-021"},{"url":"https://github.com/advisories/GHSA-68jx-f42c-7599"}],"tags":["ghsa","composer"],"epss":0.00213,"epssPercentile":0.11852,"ingestedAt":"2026-09-01T21:32:41.261Z","slug":"CVE-2026-19418","body":"## Overview\n\n### Problem\nThe referrer enforcement introduced with [TYPO3-CORE-SA-2020-006](https://news.typo3.com/security/advisory/typo3-core-sa-2020-006) ([CVE-2020-11069](https://www.cve.org/CVERecord?id=CVE-2020-11069)) became ineffective in TYPO3 v13.0, where TYPO3 CMS started serving the backend and Admin Tool applications from the site's main entry script instead of the dedicated typo3/ directory.\n\nWhether a request originated from the backend or Install Tool itself was determined by comparing the referrer against the directory of the entry script, which since then is the site root. As a consequence, requests originating from any script running on one of the TYPO3 instance's own domains, such as a frontend page, were accepted by backend routes and Install Tool endpoints.\n\nAttackers able to execute JavaScript on one of those domains, for instance by exploiting a cross-site scripting vulnerability, could invoke these endpoints via Fetch/XHR with the privileges of an authenticated victim's user session.\n\n### Solution\nUpdate to TYPO3 versions 13.4.34 LTS, 14.3.6 LTS that fix the problem described.\n\n### Credits\nThanks to Hổ Cao Từ for reporting this issue, and to TYPO3 core & security team member Benjamin Franzke for fixing it.\n\n## Affected packages\n\n- `typo3/cms-backend >= 13.0.0, < 13.4.34`\n- `typo3/cms-core >= 14.0.0, < 14.3.6`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `typo3/cms-backend 13.4.34`\n- `typo3/cms-core 14.3.6`","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":41.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}