What is CVE-2021-39608?

CVE-2021-39608 is a high-severity vulnerability in Flatcore Flatcore-Cms, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 7.2/10. Published 2021-08-23.

How severe is CVE-2021-39608?

High severity. CVSS v3 base score is 7.2 out of 10.

Arbitrary file upload in Flatcore Flatcore-Cms

CVE-2021-39608

Remote Code Execution (RCE) vulnerabilty exists in FlatCore-CMS 2.0.7 via the upload addon plugin, which could let a remote malicious user exeuct arbitrary php code.

Vulnerability class: Unrestricted File Upload

Published 2021-08-23 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.459 (98.8th percentile), scored 2026-09-29.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 99th percentile — 98.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.459 · newest: 0.459 · change: 0.000

Affected products

Flatcore Flatcore-Cms — versions 2.0.7

Weakness classification (CWE)

CWE-434 — Unrestricted Upload of File with Dangerous Type

References

github.com/flatCore/flatCore-CMS/issues/52 (Exploit, Third Party Advisory)
packetstormsecurity.com/files/164047/FlatCore-CMS-2.0.7-Remote-Code-Execution.h… (Exploit, VDB Entry, Third Party Advisory)

Frequently asked questions

What is CVE-2021-39608?: CVE-2021-39608 is a high-severity vulnerability in Flatcore Flatcore-Cms, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 7.2/10. Published 2021-08-23.
How severe is CVE-2021-39608?: High severity. CVSS v3 base score is 7.2 out of 10.