CVE-2026-8868 Single Mailchimp <= 1.4 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode Attributes
Authenticated contributors can inject arbitrary scripts via shortcode attributes in the Single Mailchimp WordPress plugin, leading to stored XSS.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-8868?
CVE-2026-8868 is a medium-severity cross-site scripting vulnerability in jonathan-robrecht Single Mailchimp, published on 27 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-79
Which versions are affected by CVE-2026-8868?
How do I fix CVE-2026-8868?
No fix has been published for CVE-2026-8868 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-8868 being exploited?
There is no known exploitation of CVE-2026-8868 in the wild and no public exploit code.
Sources
Also known as GHSA-9fg9-3rfw-p3wx.