Security readout for executives and security teams
Plain-English summary
Fork CMS 5.9.2 has a theme upload weakness that can let an attacker create or replace files under the website themes directory. This can threaten site integrity and potentially support further compromise. The sources do not confirm active exploitation, CVSS severity, authentication requirements, or a named fix.
Executive priority
Treat this as a high-priority integrity risk for any Fork CMS 5.9.2 internet-facing site. Prioritize inventory, administrative access review, and vendor-guided remediation, especially where the CMS hosts public business content.
Technical view
The CVE describes arbitrary file creation or replacement in Fork CMS 5.9.2 through a crafted ZIP uploaded in the Themes panel, targeting the /themes directory. Available sources do not define CWE, CVSS, affected version range beyond 5.9.2, required privileges, or remediation details.
Likely exposure
Exposure is most likely on Fork CMS 5.9.2 systems with the Themes panel enabled or reachable by users who can upload themes. Broader affected versions are not established in the provided sources.
Exploitation context
The CVE is not listed in KEV, and the source bundle provides no evidence of active exploitation. Public references include a GitHub repository describing the issue, but the provided evidence does not establish real-world abuse.
Researcher notes
Key gaps remain: no CVSS, CWE, affected range, authentication requirement, or patch version is supplied. The issue is source-described as arbitrary file creation or replacement in /themes via theme ZIP upload, so validation should focus on version, access controls, and file integrity.
Mitigation direction
- Check Fork CMS vendor guidance for fixed versions or upgrade instructions.
- Restrict Themes panel access to trusted administrators only.
- Review and remove unexpected files under the /themes directory.
- Back up the site before applying updates or removing theme files.
- Monitor CMS file integrity and administrative upload activity.
Validation and detection
- Identify whether any deployed site runs Fork CMS 5.9.2.
- Confirm who can access the Themes panel and upload themes.
- Inspect /themes for unexpected or recently modified files.
- Review CMS logs for theme upload activity around suspicious timestamps.
- Verify vendor advisories before declaring a version remediated.
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
File access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-28931 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/forkcms/forkcms/releases/tag/5.9.2CVE reference · x_refsource_MISC
- https://github.com/bousalman/ForkCMS-arbitrary-upload/blob/main/README.mdCVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.