CVE-2026-19418: CWE-346 Origin Validation Error in TYPO3 TYPO3 CMS
The 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 ) became ineffective in TYPO3 v13.0, where TYPO3 CMS started serving the backend and Install Tool applications from the site's main entry script instead of the dedicated typo3/ directory. Whether 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. Attackers 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. This issue affects TYPO3 CMS versions 13.0.0-13.4.33 and 14.0.0-14.3.5.
CVE-2026-19418: CWE-346 Origin Validation Error in TYPO3 TYPO3 CMS
Description
The 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 ) became ineffective in TYPO3 v13.0, where TYPO3 CMS started serving the backend and Install Tool applications from the site's main entry script instead of the dedicated typo3/ directory. Whether 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. Attackers 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. This issue affects TYPO3 CMS versions 13.0.0-13.4.33 and 14.0.0-14.3.5.
CVSS v4.0
Score 7.3high
Affected software
pkg:composer/typo3/cms-backendpkg:composer/typo3/cms-corepkg:composer/typo3/cms-installRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- TYPO3
- Date Reserved
- 2026-08-10T10:44:33.352Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a7ad257bf8831d5395884a7
Added to database: 08/11/2026, 07:42:15 UTC
Last updated: 08/11/2026, 07:42:15 UTC
Views: 1
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