CVE-2026-8868

MEDIUMCVSS 6.4/10EPSS 0.24%

Last modified

CVE-2026-8868 is a medium-severity vulnerability rated 6.4/10 on the CVSS scale. The Single Mailchimp plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'single-mailchimp' shortcode in all versions up to, and including, 1.4. This is due to insufficient input sanitization and output escaping on user-supplied shortcode attributes (autocomplete, label, placeholder, btn_text, success_msg, error_msg) which are concatenated directly into HTML output by the single_mailchimp() function in shortcodes.php. EPSS estimates a 0.24% chance of exploitation in the next 30 days.

Description

The Single Mailchimp plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'single-mailchimp' shortcode in all versions up to, and including, 1.4. This is due to insufficient input sanitization and output escaping on user-supplied shortcode attributes (autocomplete, label, placeholder, btn_text, success_msg, error_msg) which are concatenated directly into HTML output by the single_mailchimp() function in shortcodes.php. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

Metrics

CVSS 3.1
6.4/10

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

EPSS Probability
0.24%

14.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-8868?
The Single Mailchimp plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'single-mailchimp' shortcode in all versions up to, and including, 1.4. This is due to insufficient input sanitization and output escaping on user-supplied shortcode attributes (autocomplete, label, placeholder, btn_text, success_msg, error_msg) which are concatenated directly into HTML output by the single_mailchimp() function in shortcodes.php. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
How severe is CVE-2026-8868?
CVE-2026-8868 has a CVSS score of 6.4/10 (MEDIUM severity). The EPSS model estimates a 0.24% probability of exploitation in the next 30 days.
How do I fix CVE-2026-8868?
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.

Are you affected by CVE-2026-8868?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST