WordPress Plugin Vulnerabilities

Knowledge Building < 0.7.3 - Unauthenticated Stored XSS via knbu_new_reply AJAX Action

Description

The plugin does not sanitise and escape comments submitted through its reply feature, and publishes them without moderation, allowing unauthenticated users to perform Stored Cross-Site Scripting attacks against any visitor of the affected posts, including administrators.

Proof of Concept

Affects Plugins

Plugin icon
knowledge-building
Fixed in 0.7.3

References

CVE
CVE-2026-121862

Classification

Type
XSS
OWASP top 10
A7: Cross-Site Scripting (XSS)
CWE
CWE-79
CVSS
8.8 (high)

Miscellaneous

Original Researcher
Enrico Marcolini, Claudio Marchesini, Dottor Marc
Submitter
Enrico Marcolini, Claudio Marchesini, Dottor Marc
Submitter website
https://www.dottormarc.it
Verified
Yes
WPVDB ID
2656cb05-7d95-4e82-acb4-ee62a31715f8

Timeline

Publicly Published
2026-11-09 (about 2 days ago)
Added
2026-11-09 (about 1 day ago)
Last Updated
2026-11-09 (about 1 day ago)

Other

Published
Title
Published
2025-01-16
Title
HM Portfolio <= 1.1.1 - Reflected Cross-Site Scripting
Published
2026-10-01
Title
Horizontal Scrolling Announcements <= 2.6 - Contributor+ Stored XSS via Style Field
Published
2025-01-16
Title
Email to Download <= 3.1.0 - Reflected Cross-Site Scripting
Published
2024-12-02
Title
Z-Downloads < 1.11.8 - Authenticated (Administrator+) Stored Cross-Site Scripting
Published
2023-07-12
Title
MF Gig Calendar < 1.2.1 - Contributor+ Stored Cross-Site Scripting