Path traversal in baserCMS - CVE-2026-62954
Published: July 30, 2026
Vulnerability identifier: #VU140529
CSH Severity: Low
CVSS v4: 8.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-62954
CWE-ID: CWE-22
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to execute arbitrary code.
The vulnerability exists due to path traversal in the Theme File API when concatenating the ext parameter to the file name after the path-containment check. A remote privileged user can supply a crafted ext parameter containing traversal sequences to write attacker-controlled PHP into webroot/ and execute arbitrary code.
Direct external exploitation is possible when the core admin API is enabled; in the default configuration, exploitation requires chaining with another issue such as cross-site scripting.
Affected software
baserCMS
How to mitigate CVE-2026-62954
Install security update from vendor's website.
baserCMS - update to 5.3.0