How severe is CVE-2021-39608?

CVE-2021-39608 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-39608 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 46% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-39608?

CVE-2021-39608 affects Flatcore Flatcore-cms. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-39608?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-39608 published?

CVE-2021-39608 was published on 2021-08-23 and last updated on 2026-06-17.

CVE-2021-39608

CVE-2021-39608 is a high-severity vulnerability in Flatcore Flatcore-cms with a CVSS 3.x base score of 7.2. Its EPSS exploit-prediction score of 46% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-434.

Key facts

Severity: High (CVSS 3.x base score 7.2)
CVSS v2: 9.0
EPSS exploit prediction: 46% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-434
Affected product: Flatcore Flatcore-cms
Published: 2021-08-23
Last modified: 2026-06-17

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.

Frequently asked questions

What is 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.
How severe is CVE-2021-39608?: CVE-2021-39608 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-39608 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 46% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-39608?: CVE-2021-39608 affects Flatcore Flatcore-cms. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-39608?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-39608 published?: CVE-2021-39608 was published on 2021-08-23 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:flatcore:flatcore-cms:2.0.7:*:*:*:*:*:*:*

More vulnerabilities in Flatcore Flatcore-cms

CVE-2021-41403 — Critical (CVSS 9.8): flatCore-CMS version 2.0.8 calls dangerous functions, causing server-side request forgery vulnerabilities.
CVE-2017-7878 — Critical (CVSS 9.8): SQL Injection vulnerability in flatCore version 1.4.6 allows an attacker to read and write to the users database.
CVE-2021-41402 — High (CVSS 8.8): flatCore-CMS v2.0.8 has a code execution vulnerability, which could let a remote malicious user execute arbitrary PHP…
CVE-2017-7877 — High (CVSS 8.8): CSRF vulnerability in flatCore version 1.4.6 allows remote attackers to modify CMS configurations.
CVE-2017-8868 — High (CVSS 7.5): acp/core/files.browser.php in flatCore 1.4.7 allows file deletion via directory traversal in the delete parameter to…
CVE-2017-7879 — High (CVSS 7.5): SQL Injection vulnerability in flatCore version 1.4.6 allows an attacker to read the content database.

All CVEs affecting Flatcore Flatcore-cms →

Other CWE-434 (Unrestricted Upload of File with Dangerous Type) vulnerabilities

CVE-2026-48283 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Unrestricted Upload of File with Dangerous Type…
CVE-2026-48276 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Unrestricted Upload of File with Dangerous Type…
CVE-2026-57700 — Critical (CVSS 10.0): Unrestricted Upload of File with Dangerous Type vulnerability in Daan.Dev OMGF Pro allows Using Malicious Files. This…
CVE-2025-69129 — Critical (CVSS 10.0): Unauthenticated Arbitrary File Upload in WordPress & WooCommerce Scraper Plugin, Import Data from Any Site <= 1.0.7…
CVE-2026-40772 — Critical (CVSS 10.0): Unauthenticated Arbitrary File Upload in GeekyBot <= 1.2.2 versions.
CVE-2026-40412 — Critical (CVSS 10.0): Unrestricted upload of file with dangerous type in Azure Orbital Spatio allows an unauthorized attacker to execute code…

Browse all CWE-434 (Unrestricted Upload of File with Dangerous Type) vulnerabilities →