A HIGH-severity vulnerability identified as CVE-2026-19418 has been published on August 11, 2026 with a CVSS base score of 7.3. This security advisory provides a detailed breakdown of the vulnerability, its potential impact, weakness classification, and actionable steps to protect your systems.
Vulnerability Details
CVE ID: CVE-2026-19418
Severity: HIGH
CVSS Score: 7.3
Published: August 11, 2026
Weakness (CWE): CWE-346
| Attack Vector | Network |
| Attack Complexity | Low |
| Privileges Required | Low |
| User Interaction | Active |
Technical Description
The referrer enforcement introduced with TYPO3-CORE-SA-2020-006 (CVE-2020-11069) 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.
Potential Impact
If exploited, this high-severity vulnerability could allow an attacker to cause significant damage to affected systems. Organizations running affected software should treat this as a priority remediation item.
Recommended Action
No official patch is available yet. Until one is released:
- Monitor the official NVD page and vendor channels for patch announcements.
- Restrict access to the affected system or service where possible.
- Apply network-level mitigations such as firewall rules or WAF policies.
- Enable logging and alerting for anomalous activity related to this vulnerability.
- Review your incident response plan in case of active exploitation.
References
Related Security Advisories
- [HIGH] CVE-2026-19342 — CVSS 7.3 (August 9, 2026) — HIGH / CVSS 7.3
- [HIGH] CVE-2026-19343 — CVSS 7.3 (August 9, 2026) — HIGH / CVSS 7.3
- [HIGH] CVE-2026-19344 — CVSS 7.3 (August 9, 2026) — HIGH / CVSS 7.3
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