Contao 4.5.x through 4.9.x before 4.9.16, and 4.10.x through 4.11.x before 4.11.5, allows XSS. It is possible to inject code into the tl_log table that will be executed in the browser when the system log is called in the back end.
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Check my exposure →This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.