CVE detail

CVE-2020-21523 — CVE-2020-21523

Published 2020-09-30 · Modified 2026-06-17 · Vendor halo · Product halo · Source nvd

CRITICAL

severity

CVSS-derived band

9.8

CVSS v3

0–10 scale

0.0259

EPSS probability

exploitation probability, 30d

84.0%

EPSS percentile

percentile vs all CVEs

NOT LISTED

CISA KEV

known exploited catalog

Description

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")}

Remediation

No vendor-published fix data in our corpus for this CVE. Check the references below or the vendor's PSIRT / security advisories page.

References

cvedb.io · NVD · CISA KEV · FIRST EPSS · vendor advisories (CVE Program List v5). Informational only, no warranty — verify every remediation against the vendor advisory before acting on it. This product uses data from the NVD API but is not endorsed or certified by the NVD, CISA, FIRST.org or any vendor named. CVE® is a registered trademark of The MITRE Corporation.