---
id: CVE-2026-114622
title: 'baserCMS: Encoded path traversal bypass in the theme file API'
summary: >-
  baserCMS is a website development framework. In versions 5.2.3 before 5.3.2
  and 5.4.0 before 5.4.2, the optional BcThemeFile plugin's Admin API validates
  a raw path in ThemeFilesService::update() and getFullpath(), but
  ThemeFileForm::_ex…
severity: high
cvss: 7.2
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-22
  - CWE-180
vendor: baserproject
product: basercms
affected:
  - 'basercms >= 5.2.3, < 5.3.2'
  - 'basercms >= 5.4.0, < 5.4.2'
published: '2026-10-23'
updated: '2026-10-23'
sourceUpdated: '2026-10-23T13:41:33.272Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-114622'
references:
  - url: >-
      https://github.com/baserproject/basercms/security/advisories/GHSA-q7g3-qwrc-mp89
    label: >-
      https://github.com/baserproject/basercms/security/advisories/GHSA-q7g3-qwrc-mp89
  - url: >-
      https://github.com/baserproject/basercms/commit/53ecf177dfb10eb1fb89c4b42d313983329aa162
    label: >-
      https://github.com/baserproject/basercms/commit/53ecf177dfb10eb1fb89c4b42d313983329aa162
  - url: 'https://github.com/baserproject/basercms/releases/tag/5.3.2'
    label: 'https://github.com/baserproject/basercms/releases/tag/5.3.2'
  - url: 'https://github.com/baserproject/basercms/releases/tag/5.4.2'
    label: 'https://github.com/baserproject/basercms/releases/tag/5.4.2'
tags:
  - cve.org
ingestedAt: '2026-10-23T14:28:08.700Z'
---

## Overview

baserCMS is a website development framework. In versions 5.2.3 before 5.3.2 and 5.4.0 before 5.4.2, the optional BcThemeFile plugin's Admin API validates a raw path in ThemeFilesService::update() and getFullpath(), but ThemeFileForm::_execute() subsequently applies rawurldecode() to fullpath before writing. Because normalizePath() resolves only literal dot segments, percent-encoded traversal can pass the containment checks and become a path outside the theme directory at the write sink. An authenticated administrator can write PHP files into writable locations such as webroot and execute them, exceeding the intended theme-template editing boundary. The source also identifies the same check-before-decode ordering in ThemeFilesService::copy(), although that path was not dynamically verified. Exploitation requires the non-default plugin, an administrator session, and a same-origin Origin header; USE_CORE_ADMIN_API=false does not block session-authenticated requests. The Admin web form is not affected by this encoded-path tampering because FormProtection protects fullpath. This is a third bypass of the protections associated with CVE-2026-30940, using encoded traversal decoded after validation. This issue has been patched in versions 5.3.2 and 5.4.2.

## Affected

- `basercms >= 5.2.3, < 5.3.2`
- `basercms >= 5.4.0, < 5.4.2`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.