# CVE-2026-104400: bPlugins B Blocks stored cross-site scripting

Source: https://junglewise.ai/threats/cve-2026-104400-improper-neutralization-of-input-during-web-page-generation  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-05. Updated: 2026-10-05  
License: CC BY 4.0 with a link back

CVE-2026-104400 · Severity: medium · CVSS 6.5 · Published 2026-10-05

B Blocks is a WordPress plugin that enables block-based content creation for websites. A stored cross-site scripting (XSS) vulnerability in versions up to 2.1.8 allows an authenticated attacker with contributor or higher privileges to inject malicious scripts that execute for all site visitors, potentially stealing data or hijacking user accounts.

Technologies: [bPlugins B Blocks](https://junglewise.ai/threats/technologies/b-blocks). Vendors: [bPlugins](https://junglewise.ai/threats/vendors/bplugins).

## Quick answers

**Is CVE-2026-104400 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-104400 being exploited in the wild.

**How severe is CVE-2026-104400?** Medium severity, with a CVSS score of 6.5, published 5 October 2026.

**Which products and versions are affected?** bPlugins B Blocks up to 2.1.8.

**Is there a fix for CVE-2026-104400?** Yes: fixed in 2.1.9. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-104400 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-104400?** Check whether you run bPlugins B Blocks at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 2.1.9

## Technical details

A stored XSS vulnerability exists in B Blocks where user-supplied input is not properly sanitized during web page generation. An attacker with contributor or developer role privileges can inject malicious JavaScript that persists in the database and executes in the browsers of all visitors to the affected pages. The vulnerability requires user interaction (privileged user action) to be exploited.

## Affected products

- bPlugins B Blocks up to 2.1.8

## Timeline

- 2026-08-06: disclosed: Reported to Patchstack by V1T
- 2026-10-05: advisory: Published by Patchstack

## References

- [https://wordpress.org/plugins](https://wordpress.org/plugins)
- [https://patchstack.com/database/wordpress/plugin/b-blocks/vulnerability/wordpress-b-blocks-plugin-2-1-8-cross-site-scripting-xss-vulnerability?_s_id=cve](https://patchstack.com/database/wordpress/plugin/b-blocks/vulnerability/wordpress-b-blocks-plugin-2-1-8-cross-site-scripting-xss-vulnerability?_s_id=cve)

## Related threats

- [bPlugins B Blocks stored cross-site scripting](https://junglewise.ai/threats/cve-2026-125451-improper-neutralization-of-input-during-web-page-generation)
- [bPlugins B Blocks privilege escalation in WordPress plugin](https://junglewise.ai/threats/cve-2026-39579-bplugins-b-blocks-privilege-escalation-in-wordpress-plugin)