How severe is CVE-2021-28931?

CVE-2021-28931 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-28931 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-28931?

CVE-2021-28931 affects Fork-cms Fork Cms. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-28931?

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-2021-28931 published?

CVE-2021-28931 was published on 2021-07-07 and last updated on 2026-06-17.

CVE-2021-28931

CVE-2021-28931 is a high-severity vulnerability in Fork-cms Fork Cms with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-434.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.5
EPSS exploit prediction: 1% (65th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-434
Affected product: Fork-cms Fork Cms
Published: 2021-07-07
Last modified: 2026-06-17

Description

Arbitrary file upload vulnerability in Fork CMS 5.9.2 allows attackers to create or replace arbitrary files in the /themes directory via a crafted zip file uploaded to the Themes panel.

Frequently asked questions

What is CVE-2021-28931?: Arbitrary file upload vulnerability in Fork CMS 5.9.2 allows attackers to create or replace arbitrary files in the /themes directory via a crafted zip file uploaded to the Themes panel.
How severe is CVE-2021-28931?: CVE-2021-28931 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-28931 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (65th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-28931?: CVE-2021-28931 affects Fork-cms Fork Cms. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-28931?: 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-2021-28931 published?: CVE-2021-28931 was published on 2021-07-07 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:fork-cms:fork_cms:5.9.2:*:*:*:*:*:*:*

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