Block for Mailchimp – Add Email Subscription Forms and Collect Leads <= 1.1.15 - Missing Authorization
Strategic Overview
- Status
- Patched in 1.1.16
- Affected Plugin
- Block for Mailchimp – grow your email list with signup forms
- Affected Version
<= 1.1.15- CVSS
- 5.3Medium
- Weakness type
- CWE-862 · Missing Authorization
- CVE
CVE-2026-56063
At a glance
CVE-2026-56063 is a medium-severity Missing Authorization vulnerability in the Block for Mailchimp WordPress plugin, affecting versions <= 1.1.15. It carries a CVSS score of 5.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 1.1.16; sites on affected versions should update now. Disclosed June 2026, reported by Nguyen Quang Truong.
Vulnerability Overview
The Block for Mailchimp – Add Email Subscription Forms and Collect Leads plugin for WordPress is vulnerable to unauthorized access due to a missing capability check on a function in versions up to, and including, 1.1.15. This makes it possible for unauthenticated attackers to perform an unauthorized action.
Technical Analysis
The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site, and no interaction from a victim user.
CWE-862: Missing Authorization
Reaching this weakness in Block for Mailchimp <= 1.1.15 takes a caller who can reach the endpoint. A missing authorization check means a function is reachable by anyone who can reach the endpoint, because the code never asks whether the caller is allowed to perform the action.
Any user who can reach the endpoint gets to run an action reserved for higher-privileged roles, from reading protected data to changing settings or content. For Block for Mailchimp the fix is 1.1.16: builds <= 1.1.15 are affected, anything from 1.1.16 onward is not.
Remediation
Update to version 1.1.16, or a newer patched version
How does WordSec protect against this?
Because it turns on account access, WordSec's login security is the relevant layer: role-based two-factor, captcha and brute-force limits raise the cost of getting the account this needs. None of that substitutes for the fix: Block for Mailchimp 1.1.16 closes this, and updating the plugin is the step that ends it.
- Login Security
- Alerts
External References
Related records
Other vulnerabilities in Block for Mailchimp – grow your email list with signup forms
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