CVE-2021-39608Flatcore-CMS Unrestricted File Upload
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.
Published Aug 23, 2021 · Updated Jul 9, 2026
Key Facts
Patch immediately- CVE-2021-39608 is a high-severity vulnerability (CVSS 7.2 v3.1) affecting Flatcore-CMS.
- It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
- EPSS estimates a 46% probability of exploitation in the next 30 days.
- No fixed version is listed yet; check the vendor advisory for mitigations.
- Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
Scores
CVSS v3.1
7.2
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
46%
Higher than 98.7% of all scored CVEs
Exploit maturity
Proof of concept
ATLAS score
44/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Not listed
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
Proof of concept
Public exploit code
3
Proof-of-concept links
In-the-wild evidence
0
Reports of active use
Description
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.
Affected Products
1 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Flatcore-CMSFlatcore | 2.0.7 | n/a |
Timeline
Publicly disclosed
Aug 23, 2021
Last updated
Jul 9, 2026
Weakness Type
- CWE-434 Unrestricted Upload of File with Dangerous Type
References
FAQ
Common Questions.
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.
Affected: Flatcore-CMS versions 2.0.7. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because public exploit code exists for a high-severity flaw.
Is CVE-2021-39608 On Your Attack Surface?
Brandefense matches it against the products discovered on your perimeter and opens a finding the day a CVE like this is listed.
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