What’s Vulnerable › Vulnerabilities

CVE-2026-30940: baserCMS: Path Traversal in Theme File API Leads to Arbitrary File Write and RCE

• Severity: high (CVSS 7.2 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.0% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-03-31 · updated 2026-06-17
• Weakness: CWE-22

Description

baserCMS is a website development framework. Prior to version 5.2.3, a path traversal vulnerability exists in the theme file management API (/baser/api/admin/bc-theme-file/theme_files/add.json) that allows arbitrary file write. An authenticated administrator can include ../ sequences in the path parameter to create a PHP file in an arbitrary directory outside the theme directory, which may result in remote code execution (RCE). This issue has been patched in version 5.2.3.

Affected products

• baserproject basercms: before 5.2.3 — fixed in 5.2.3

How to fix

Upgrade to a fixed version: baserproject basercms 5.2.3. Check the vendor advisory for mitigations.

References

• https://basercms.net/security/JVN_20837860
• https://github.com/baserproject/basercms/releases/tag/5.2.3
• https://github.com/baserproject/basercms/security/advisories/GHSA-c5c6-37vq-pjcq

Get alerted when CVE-2026-30940 or the next vulnerability affects your stack