CVE-2021-28931: Arbitrary file upload in Fork CMS

high Affects forkcms/forkcms. Feed 2026.10.29.4, updated 2026-10-29; published 2021-09-08; advisory modified 2023-11-08.

Arbitrary file upload in Fork CMS

Package: forkcms/forkcms Composer
Affected versions: <5.9.3
Fixed in: 5.9.3
Severity: high CVSS 8.8
Exploitation: not on CISA KEV · EPSS 1% (68.4th percentile)
Published: 2021-09-08
Source: osv.dev

References

CWE-434

NVD record forkcms/forkcms advisories

Am I affected?

Find out in one command. phpwarden checks your composer.lock against this advisory and 20,000+ others, ranked by real-world exploitation (CISA KEV + EPSS). Free, offline, open data.

# PHP projects (recommended)
composer require --dev phpwarden/phpwarden
# then
vendor/bin/phpwarden deps composer.lock

# or, without Composer
pipx install phpwarden   &&   phpwarden deps composer.lock

Or keep it checked automatically: GitHub Action · pre-commit hook · GitLab CI · Laravel artisan command

Install docs How findings are ranked

Related advisories

CVE-2012-1188 medium Fork CMS Multiple XSS Vulnerabilities same package: forkcms/forkcms
CVE-2012-1207 medium ForkCMS Directory Traversal vulnerability same package: forkcms/forkcms
CVE-2022-1064 high SQL Injection in Fork CMS same package: forkcms/forkcms
CVE-2022-0153 high SQL Injection in Fork CMS same package: forkcms/forkcms
CVE-2012-1209 medium Fork CMS XSS via Highlight Parameter same package: forkcms/forkcms
CVE-2020-23263 medium Cross-site scripting in forkcms same package: forkcms/forkcms