# Kit (formerly ConvertKit) – Email Subscribers, Email Newsletter, Email Marketing, Landing Pages and Membership <= 3.5.0 - Unauthenticated Sensitive Information Exposure via Restricted Post Attachments

- **ID:** WPSEC-2026-2850
- **Plugin:** Kit (formerly ConvertKit) – Email Subscribers, Email Newsletter, Email Marketing, Landing Pages and Membership (`convertkit`), https://wordpress.org/plugins/convertkit/
- **Affected versions:** from 2.1.0 before 3.5.1
- **Fixed in:** 3.5.1 (Update to 3.5.1 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-200
- **Usage among sites WPSec scans:** plugin Medium, affected versions Medium (as of 2026-11-12)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/convertkit
- **Fix released:** 2026-11-10
- **Published:** 2026-11-12
- **URL:** https://wpsec.com/vuln/WPSEC-2026-2850/

## Description

The Kit (formerly ConvertKit) plugin for WordPress is vulnerable to Sensitive Information Exposure in all versions up to, and including, 3.5.0 due to the Member Content feature not restricting attachments of restricted pages and posts in the REST API and on attachment pages. This makes it possible for unauthenticated attackers to obtain the file URLs of media attached to member-only content and access those files.

## References

- https://wpsec.com/vuln/WPSEC-2026-2850/
- https://plugins.svn.wordpress.org/convertkit/tags/3.5.1/
- https://wordpress.org/plugins/convertkit/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-2850/

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.