Cross-site scripting in the system log

Date: 2021-06-23
CVE ID: CVE-2021-35210

Description

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. The attacker does not have to be logged in.

Affected versions

Contao 4.5
Contao 4.6
Contao 4.7
Contao 4.8
Contao 4.9 up to 4.9.15
Contao 4.10
Contao 4.11 up to 4.11.4

Suggested solution

Update to Contao 4.9.16 or 4.11.5.

Workaround

Disable the system log module in the back end for all users (especially admin users).

More information

https://github.com/contao/contao/security/advisories/GHSA-h58v-c6rf-g9f7