Knowledge Building WordPress plugin: Reflected cross-site scripting
Summary
The Knowledge Building WordPress plugin before version 0.7.3 does not escape several user-supplied values before returning them in the response of an AJAX action. The response is served as HTML, so injected script code is executed in the browser. The AJAX action is available to unauthenticated users, but exploitation requires a victim to open a crafted link, and the attacker could then act in the victim's session with the victim's rights.
Affected
- Knowledge Building WordPress plugin, all versions before 0.7.3
Fixed in
- Version 0.7.3 (according to the CVE record and WPScan)
Workaround
- Unknown. No vendor workaround found.
- If the update cannot be applied, deactivate or remove the plugin.
Exploitation
- No known exploitation in the wild at the time of writing.
- No public proof of concept found in Metasploit, Exploit-DB or nuclei indexes as of 10 Nov 2026. The WPScan reference is tagged as an exploit in CVE metadata; this has not been verified.
Our recommendation
- Check whether the Knowledge Building plugin is installed on any WordPress site and which version it runs.
- Update to version 0.7.3 or later, or deactivate the plugin if an update is not possible.
- Re-check the NVD entry and the WPScan page once the CVSS score is confirmed and any proof of concept is published.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- CVE Record CVE-2026-121863 www.cve.org
- WPScan advisory wpscan.com
- Offseq radar: CVE-2026-121863 radar.offseq.com
- Strix CVE entry www.strix.ai
- threatint CVE entry cve.threatint.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 11 Nov 2026, 13:33.
Original description (NVD)
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.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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