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

ID

WPSEC-2026-2853

Plugin

Kit (formerly ConvertKit) – Email Subscribers, Email Newsletter, Email Marketing, Landing Pages and Membership (convertkit)

Affected

from 2.1.0 before 3.5.1

Remediation

Update to 3.5.1 or later.

CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Weakness

CWE-200

Usage

Plugin Medium · Affected versions Medium among sites WPSec scans, 2026-11-12

Attack surface

Kit (formerly ConvertKit) – Email Subscribers, Email Newsletter, Email Marketing, Landing Pages and Membership on WPSec AttackSurface

Fix released

2026-11-10

Published

2026-11-12

Description

The Kit (formerly ConvertKit) plugin for WordPress is vulnerable to Sensitive Information Exposure via the REST API in all versions up to, and including, 3.5.0. This is due to the Member Content restriction on REST API responses replacing only the rendered content of restricted posts. It leaves the excerpt that WordPress generates from the post content unchanged, and it skips the restriction entirely when only the excerpt is requested through the _fields parameter. This makes it possible for unauthenticated attackers to read member-only content of restricted pages and posts.

References

• https://wpsec.com/vuln/WPSEC-2026-2853/
• https://plugins.svn.wordpress.org/convertkit/tags/3.5.1/
• https://wordpress.org/plugins/convertkit/

Published by WPSec. Provided as is, without warranty. Corrections: contact us.

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