---
id: "CVE-2026-121863"
page: "https://infrastack.ai/live/CVE-2026-121863"
kind: "vulnerability"
aliases: ["CVE-2026-121863"]
title: "Knowledge Building WordPress plugin: reflected cross-site scripting via unauthenticated AJAX action"
severity: "medium"
cvss: null
epss: null
exploited: false
status: "open"
category: "other"
products: []
ecosystems: []
tags: ["knowledge-building", "other", "wordpress"]
not_affected_if: ["plugin-not-installed", "version-0.7.3-or-later"]
published_at: "2026-11-11T06:17:16+00:00"
first_seen_at: "2026-11-11T06:25:42+00:00"
updated_at: "2026-11-11T06:27:30+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121863", "first_seen_at": "2026-11-11T06:25:42+00:00"}]
exploit_sources: []
---

# Knowledge Building WordPress plugin: reflected cross-site scripting via unauthenticated AJAX action

Link for people: https://infrastack.ai/live/CVE-2026-121863 (this .md is for agents)

The Knowledge Building WordPress plugin before 0.7.3 echoes several user-supplied values back unescaped in an AJAX response served as HTML. An attacker can craft a link that runs script in a visitor's browser, in the context of the affected site.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed version of the Knowledge Building plugin in the WordPress admin under Plugins; versions below `0.7.3` are affected.

## Fix

- Knowledge Building plugin: move to `0.7.3` or later, per the advisory's stated fixed version.

## Timeline

- 2026-11-11T06:25:42+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-121863

## From the sources

The Knowledge Building WordPress plugin before 0.7.3 does not escape several user-supplied values before echoing them back in the response of an AJAX action available to unauthenticated users, and serves that response as HTML, leading to a Reflected Cross-Site Scripting.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_