baserCMS File Uploader Remote Code Execution (RCE) vulnerabilityGHSA-h4cc-fxpp-pgw9
CRITICALFix: baserproject/basercms@002886bGHSA-h4cc-fxpp-pgw9 is a critical-severity (CVSS 9.8) Unrestricted File Upload vulnerability in baserproject/basercms. A fix is available for baserproject/basercms — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-h4cc-fxpp-pgw9.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
baserproject/basercmsReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Impact
There is a Remote Code Execution (RCE) Vulnerability on the management system of baserCMS.
Target
baserCMS 4.7.3 and earlier versions
Patches
Update to the latest version of baserCMS
Credits
島峰泰平＠三井物産セキュアディレクション株式会社
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | baserproject/basercms | all versions | 4.7.5composer require baserproject/basercms:^4.7.5 |
Affected Products
basercmsbasercmsDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for baserproject/basercms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update baserproject/basercms to 4.7.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-h4cc-fxpp-pgw9 is resolved across your whole dependency graph.
Workarounds
Treat uploaded files as untrusted until proven otherwise: validate the actual content type rather than the supplied extension, store uploads outside the web root on a volume mounted without execute permission, and rename them to server-generated identifiers so an attacker cannot choose the path a request will later resolve.
Frequently Asked Questions
Is GHSA-h4cc-fxpp-pgw9 in your dependencies?
Find it across Packagist, including transitive dependencies.