What is CVE-2020-21237?

CVE-2020-21237 is a critical-severity vulnerability in 8cms Ljcms, classified under Improper Restriction of Excessive Authentication Attempts. CVSS score: 9.8/10. Published 2021-12-27.

How severe is CVE-2020-21237?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Vulnerability in 8cms Ljcms

CVE-2020-21237

An issue in the user login box of LJCMS v1.11 allows attackers to hijack user accounts via brute force attacks.

Published 2021-12-27 · last modified 2026-06-17.

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: 0.011 (64.2th percentile), scored 2026-10-01.

Low probability of exploitation in the next 30 days, but still tracked. 64th percentile — 64.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000

Affected products

8cms Ljcms — versions 1.11

Weakness classification (CWE)

CWE-307 — Improper Restriction of Excessive Authentication Attempts

References

github.com/wind-cyber/LJCMS-UserTraversal-Vulnerability (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2020-21237?: CVE-2020-21237 is a critical-severity vulnerability in 8cms Ljcms, classified under Improper Restriction of Excessive Authentication Attempts. CVSS score: 9.8/10. Published 2021-12-27.
How severe is CVE-2020-21237?: Critical severity. CVSS v3 base score is 9.8 out of 10.