What is CVE-2020-20979?

CVE-2020-20979 is a critical-severity vulnerability in 8cms Ljcms, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 9.8/10. Published 2021-08-12.

How severe is CVE-2020-20979?

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

Arbitrary file upload in 8cms Ljcms

CVE-2020-20979

An arbitrary file upload vulnerability in the move_uploaded_file() function of LJCMS v4.3 allows attackers to execute arbitrary code.

Vulnerability class: Unrestricted File Upload

Published 2021-08-12 · 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: 0.016 (74.9th percentile), scored 2026-10-01.

Low probability of exploitation in the next 30 days, but still tracked. 75th percentile — 74.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.016 · newest: 0.016 · change: 0.000

Affected products

8cms Ljcms — versions 4.3.-

Weakness classification (CWE)

CWE-434 — Unrestricted Upload of File with Dangerous Type

References

github.com/0xyu/PHP_Learning/issues/2 (Exploit, Third Party Advisory, Issue Tracking)

Frequently asked questions

What is CVE-2020-20979?: CVE-2020-20979 is a critical-severity vulnerability in 8cms Ljcms, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 9.8/10. Published 2021-08-12.
How severe is CVE-2020-20979?: Critical severity. CVSS v3 base score is 9.8 out of 10.