# CMB2 <= 2.13.3 - Unauthenticated Sensitive Information Exposure via REST API Field Endpoints

- **ID:** WPSEC-2026-0728
- **Plugin:** CMB2 (`cmb2`), https://wordpress.org/plugins/cmb2/
- **Affected versions:** from 2.2.3 before 2.13.4
- **Fixed in:** 2.13.4 (Update to 2.13.4 or later.)
- **Severity:** Medium 5.3 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N)
- **Weakness:** CWE-862
- **Usage among sites WPSec scans:** plugin Low, affected versions None seen (as of 2026-10-10)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/cmb2
- **Fix released:** 2026-10-09
- **Published:** 2026-10-10
- **URL:** https://wpsec.com/vuln/WPSEC-2026-0728/

## Description

The CMB2 plugin for WordPress is vulnerable to Sensitive Information Exposure via the REST API field endpoints (/cmb2/v1/boxes/{box}/fields and /fields/{field}) in versions 2.2.3 up to, and including, 2.13.3. The plugin does not check whether the requester may read the object named by the 'object_id' parameter. This makes it possible for unauthenticated attackers to read the CMB2 field values of draft, pending, private, future or trashed posts, of posts whose type is not shown in the REST API and is not one of the box's post types, of unapproved comments, and of comments on posts they cannot read. Only metaboxes that are exposed through the REST API (show_in_rest) are affected.

## References

- https://wpsec.com/vuln/WPSEC-2026-0728/
- https://plugins.svn.wordpress.org/cmb2/tags/2.13.4/
- https://wordpress.org/plugins/cmb2/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-0728/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Free to use, share and adapt, also commercially, if you credit WPSec and link to this advisory.