What is CVE-2020-36389?

CVE-2020-36389 is a medium-severity vulnerability in Civicrm, classified under Cross-Site Request Forgery (CSRF). CVSS score: 4.3/10. Published 2021-06-17.

How severe is CVE-2020-36389?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Is CVE-2020-36389 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

CSRF in Civicrm

CVE-2020-36389

In CiviCRM before 5.28.1 and CiviCRM ESR before 5.27.5 ESR, the CKEditor configuration form allows CSRF.

Vulnerability class: CSRF (Cross-Site Request Forgery)

Published 2021-06-17 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N.

EPSS exploit prediction

EPSS: 0.007 (49.7th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 49.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.007 · newest: 0.007 · change: 0.000

Affected products

Civicrm

Weakness classification (CWE)

CWE-352 — Cross-Site Request Forgery (CSRF)

Public proof-of-concept exploits

References

civicrm.org/advisory/civi-sa-2020-11-csrf-ckeditor-configuration-form (Vendor Advisory)
blog.sonarsource.com/civicrm-code-execution-vulnerability-chain-explained/ (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2020-36389?: CVE-2020-36389 is a medium-severity vulnerability in Civicrm, classified under Cross-Site Request Forgery (CSRF). CVSS score: 4.3/10. Published 2021-06-17.
How severe is CVE-2020-36389?: Medium severity. CVSS v3 base score is 4.3 out of 10.
Is CVE-2020-36389 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.