CVE-2026-104400 WordPress B Blocks plugin <= 2.1.8 - Cross Site Scripting (XSS) vulnerability
Stored XSS in B Blocks plugin allows attackers to inject malicious scripts, potentially leading to session hijacking or site defacement.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-104400?
CVE-2026-104400 is a medium-severity cross-site scripting vulnerability in bPlugins B Blocks, published on 5 Oct 2026. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Official description
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in bPlugins B Blocks b-blocks allows Stored XSS.This issue affects B Blocks: from n/a through 2.1.8.
Weakness: CWE-79
Which versions are affected by CVE-2026-104400?
How do I fix CVE-2026-104400?
No fix has been published for CVE-2026-104400 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-2026-104400 being exploited?
There is no known exploitation of CVE-2026-104400 in the wild and no public exploit code.
Sources
Also known as GHSA-fc88-8573-9hfx.