CVE-2020-21523: Halo

Critical severity, CVSS 9.8. EPSS: 2.6% chance of exploitation in the next 30 days.

A Server-Side Freemarker template injection vulnerability in halo CMS v1.1.3 In the Edit Theme File function. The ftl file can be edited. This is the Freemarker template file. This file can cause arbitrary code execution when it is rendered in the background. exp: <#assign test="freemarker.template.utility.Execute"?new()> ${test("touch /tmp/freemarkerPwned")}

Affected products

• Halo Halo: version 1.1.3 only

Published 2020-09-30. Last modified 2026-06-17.