CVE-2026-8727: TYPO3 Extension Site Crawler

High severity, CVSS 7.1. EPSS: 0.5% chance of exploitation in the next 30 days.

The Crawler extension passes the X-T3Crawler-Meta response header from crawled URLs directly to PHP's unserialize(). An attacker controlling a crawled endpoint can inject arbitrary serialized PHP objects, leading to Remote Code Execution on the TYPO3 server. Exploitation requires administrative privileges to configure a crawler-enabled page and trigger the crawl via a Scheduler task.

Affected products

• TYPO3 Extension Site Crawler: from 12.0.0, before 12.0.11 (fixed in 12.0.11); before 11.0.13 (fixed in 11.0.13)

Published 2026-05-19. Last modified 2026-06-17.