CVE-2026-30877 — basercms
CRITICALCVE-2026-30877 is a critical-severity (CVSS 9.1) OS Command Injection vulnerability in baserproject/basercms. A fix is available for baserproject/basercms — see the affected versions and patch details below.
baserCMS: OS Command Injection in the baserCMS Update Functionality
Exploitation Status
No confirmed exploitation observed yet
- 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 CVE-2026-30877.
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
Summary
The latest version of baserCMS (basercms-5.2.2) contains an OS command injection vulnerability (CWE-78) in its update functionality. Due to this issue, an authenticated user with administrator privileges in baserCMS can execute arbitrary OS commands on the server with the privileges of the user account running baserCMS.
Details
Please refer to the attached materials. OSコマンドインジェクション（baserCMSのアップデート機能）.pdf
Impact
An authenticated user with administrator privileges in baserCMS can execute OS commands on the server with the privileges of the user account running baserCMS.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | baserproject/basercms | all versions | 5.2.3composer require baserproject/basercms:^5.2.3 |
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 5.2.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-30877 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.
Frequently Asked Questions
Is CVE-2026-30877 in your dependencies?
Find it across Packagist, including transitive dependencies.