What’s Vulnerable › Vulnerabilities

CVE-2021-35210

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.7% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-06-23 · updated 2026-06-17
• Weakness: CWE-79

Description

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.

Affected products

• contao: from 4.5.0 before 4.9.16; from 4.10.0 before 4.11.5 — fixed in 4.11.5, 4.9.16

How to fix

Upgrade to a fixed version: contao 4.11.5, 4.9.16. Check the vendor advisory for mitigations.

References

• https://contao.org/en/security-advisories/cross-site-scripting-in-the-system-log-2021.html
• https://github.com/contao/contao/security/advisories/GHSA-h58v-c6rf-g9f7
• https://contao.org/en/security-advisories/cross-site-scripting-in-the-system-log-2021.html
• https://github.com/contao/contao/security/advisories/GHSA-h58v-c6rf-g9f7

Get alerted when CVE-2021-35210 or the next vulnerability affects your stack