VulnerabilityPublished 11 Nov 2026

CVE-2026-121863: Knowledge Building (WordPress plugin) · Cross-site Scripting

Affects Knowledge Building (WordPress plugin)Source CVE Database V5

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Not known to be exploited : upgrade to 0.7.3 soon.

Data as of 11 Nov 2026, 06:33 UTC

Severity

High

Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none

Patch: Available – fixed in 0.7.3

Exploitation evidence

Disclosed: evidence found.
CVE published 11 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 10 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Knowledge Building (WordPress plugin) to 0.7.3.

Affected software

Product	Affected	Fixed in
Knowledge Building	Affected <0.7.3	Fixed in 0.7.3

AI-suggested

Upgrade the Knowledge Building plugin to version 0.7.3 or later, where this vulnerability has been fixed by properly escaping user-supplied input before output. No other mitigations are indicated by the vendor advisory.

Description

A reflected Cross-Site Scripting (XSS) vulnerability exists in the Knowledge Building WordPress plugin versions before 0.7.3. The flaw arises because several user-supplied values are not properly escaped before being echoed back in the response of an AJAX action accessible to unauthenticated users, with the response served as HTML. This allows an attacker to inject malicious scripts that could execute in the context of users viewing the affected content.

Impact

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary JavaScript in the context of users interacting with the vulnerable AJAX endpoint. This may lead to session hijacking, defacement, or other malicious actions performed on behalf of the victim. However, there are no known exploits in the wild at this time.

Summary

The Knowledge Building WordPress plugin prior to version 0.7.3 contains a reflected Cross-Site Scripting (CWE-79) vulnerability. This occurs because the plugin fails to escape multiple user-supplied input values before including them in the HTML response of an AJAX action that is accessible without authentication. As a result, an attacker can craft a malicious request that causes arbitrary scripts to be executed in the victim's browser when the response is rendered.

CWE-79Improper Neutralization of Input During Web Page Generation (Cross-site Scripting) (opens in a new tab)
Base weaknessLikelihood of exploit: HighCWE Top 25 (2025): #1OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Implementation · Architecture and Design
Understand the context in which your data will be used and the encoding that will be expected. This is especially important when transmitting data between different components, or when generating outputs that can contain multiple encodings at the same time, such as web pages or multi-part mail messages.
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter your software: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide…
OWASP Cheat Sheets
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Injection Prevention (opens in a new tab)
Abuse Case (opens in a new tab)
Deserialization (opens in a new tab)
OWASP ASVS 4.0.3
V5.3.3 (opens in a new tab)
V1.5.1 (opens in a new tab)
Attack patterns
XSS Using MIME Type Mismatch (opens in a new tab)
DOM-Based XSS (opens in a new tab)
Reflected XSS (opens in a new tab)
Stored XSS (opens in a new tab)
Cross-Site Scripting (XSS) (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

wpscan.com/vulnerability/80b4b9d0-e48b-4f24-b4bd-71dc37ac1602/ (opens in a new tab)

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 11 Nov 2026, 06:33 UTC

WeaknessesCWE-79

Technical details

References

Community reviews

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