CVE-2026-0691: The CM E-Mail Blacklist – Simple email filtering for safer registration plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'bla...

Description

The CM E-Mail Blacklist – Simple email filtering for safer registration plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'black_email' parameter in all versions up to, and including, 1.6.2. This is due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.

Metrics

CVSS 3.1

4.4/10

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

EPSS Probability

0.26%

17.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

References

Timeline

Published: Jan 17, 2026
Last Modified: Jun 17, 2026
Status: Deferred

Frequently Asked Questions

What is CVE-2026-0691?

The CM E-Mail Blacklist – Simple email filtering for safer registration plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'black_email' parameter in all versions up to, and including, 1.6.2. This is due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with administrator-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.

How severe is CVE-2026-0691?

CVE-2026-0691 has a CVSS score of 4.4/10 (MEDIUM severity). The EPSS model estimates a 0.26% probability of exploitation in the next 30 days.

How do I fix CVE-2026-0691?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.