CVE-2026-8891 BitForm <= 1.1.0 - Authenticated (Contributor+) Stored Cross-Site Scripting via Shortcode Attributes
Authenticated attackers can inject arbitrary scripts via shortcode attributes, leading to code execution when users view affected pages.
- 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-2026-8891?
CVE-2026-8891 is a medium-severity cross-site scripting vulnerability in BitForm – Data management solution for WordPress, published on 27 May 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
The BitForm plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'bitform' shortcode in versions up to, and including, 1.1.0. This is due to insufficient input sanitization and output escaping on user-supplied shortcode attributes ('width' and 'height') in the Shortcode::shortcode() function, which are interpolated directly into the 'style' attribute of an <iframe> element. 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-2026-8891?
How do I fix CVE-2026-8891?
No fix has been published for CVE-2026-8891 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-2026-8891 being exploited?
There is no known exploitation of CVE-2026-8891 in the wild and no public exploit code.
Sources
Also known as GHSA-fqhh-m4m2-4pc6.