CVE-2021-28931 json
Arbitrary file upload in Fork CMS
published 2021-07-07 5 y ago modified 2026-06-17 4 mo ago also GHSA-748f-wv76-x9hg , EUVD-2021-2001
- cvss
- 8.8
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.2%
- EPSS 1.2% chance of exploitation in 30 days, percentile 68%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- packagist forkcms/forkcms 5.9.3
- github.com/forkcms/forkcms#3351 pull request
- github.com/forkcms/forkcms/releases/tag/5.9.2 release
Exploit prediction
1.21% chance of exploitation in the next 30 days, higher than 68% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 6.5 | AV:N/AC:L/Au:S/C:P/I:P/A:P |
| GitHub | 3.1 | 8.8 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| packagist | forkcms/forkcms | <5.9.3 |
5.9.3 |
Classification
- Weakness
-
- CWE-434 Unrestricted Upload of File with Dangerous Type
References
-
github.com
/forkcms/forkcms/pull/3351
web
-
github.com
/forkcms/forkcms/releases/tag/5.9.2
web, release-notes, third-party-advisory
-
github.com
/bousalman/ForkCMS-arbitrary-upload/blob/main/README.md
web, third-party-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2021-28931
advisory
Sources
- CVE List CVE-2021-28931
- GitHub Advisory GHSA-748f-wv76-x9hg
- NVD CVE-2021-28931
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