Vulnerability in Halo

CVE-2020-21523

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")}

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.026 (84.7th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 85th percentile — 84.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2020-21523: held from 0.026 to 0.026.

EPSS over last 30 days · oldest: 0.026 · newest: 0.026 · change: 0.000

Affected products

  • Halo — versions 1.1.3

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2020-21523?
CVE-2020-21523 is a critical-severity vulnerability in Halo, classified under Improper Neutralization of Special Elements in Output Used by a Downstream Component (Injection). CVSS score: 9.8/10. Published 2020-09-30.
How severe is CVE-2020-21523?
Critical severity. CVSS v3 base score is 9.8 out of 10.