High severity · published Mar 31, 2026
CVE-2026-30940
baserCMS: Path Traversal in Theme File API Leads to Arbitrary File Write and RCE
7.2
CVSS
1.1%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
High
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.1% · higher than 65% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
BA
basercms · baserproject
< 5.2.3 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-30940
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-30940
Vendor Advisory
https://basercms.net/security/JVN_20837860
Release Notes
https://github.com/baserproject/basercms/releases/tag/5.2.3
Exploit
https://github.com/baserproject/basercms/security/advisories/GHSA-c5c6-37vq-pjcq
More from basercms
9.8
CVE-2026-30880
baserCMS: OS command injection vulnerability in installer
9.8
CVE-2026-27697
baserCMS: SQL injection vulnerability in blog post
9.8
CVE-2023-43792
baserCMS Code Injection Vulnerability in Mail Form Feature
9.8
CVE-2023-43649
baserCMS CSRF vulnerability in Content preview Feature
8.8
CVE-2026-114621
baserCMS: SQL injection in the admin panel and admin API