Kubio AI Page Builder: Unauthenticated stored Cross-Site Scripting
Summary
The Kubio AI Page Builder WordPress plugin before 2.9.3 applies an expanded list of allowed HTML elements to content submitted by unauthenticated users, not only in the editor. An unauthenticated attacker can store malicious markup that the plugin then executes in the browser of any visitor, including an administrator who reviews the pending submission. The attack requires user interaction (UI:R) and works on sites that accept public submissions such as comments.
Affected
- Kubio AI Page Builder WordPress plugin, all versions before 2.9.3 (vendor-side range per Freshysites and VulDB: up to 2.9.2)
Fixed in
- Fixed in 2.9.3
- The WordPress.org changelog also lists 2.9.4 and 2.9.4-pro with further XSS fixes. Use 2.9.4 or later.
Workaround
Unknown. No vendor-documented interim workaround was found. Updating is the mitigation.
Exploitation
- No evidence of exploitation in the wild found in the sources.
- CISA SSVC assessment: exploitation none, automatable no, technical impact total.
- Public proof of concept: unknown.
- One third-party aggregator lists the entry as not in KEV; this was not confirmed on cisa.gov.
Our recommendation
- Identify all WordPress sites running Kubio and check the installed version.
- Update to 2.9.4 or later, at minimum 2.9.3, and verify the version on each site.
- Review pending comments and submissions for suspicious markup. Limit comment submission rights where practical.
- Protect administrator accounts and review them. Consider stronger session protection.
- Monitor the NVD record, as analysis was still pending at the time of research.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- WPScan: Kubio AI Page Builder < 2.9.3 Unauthenticated Stored XSS wpscan.com
- WordPress.org: Kubio AI Page Builder plugin (changelog) wordpress.org
- Freshysites security bulletin CVE-2026-88783 freshysites.com
- VulDB: CVE-2026-88783 vuldb.com
- Strix: CVE-2026-88783 www.strix.ai
- Rapid7 Vulners: CVE-2026-88783 vulners.com
- Positive Technologies Vulners: PT-2026-104528 vulners.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 31 Oct 2026, 22:40.
Original description (NVD)
The Kubio AI Page Builder WordPress plugin before 2.9.3 does not limit its widening of the allowed HTML elements to the editor context, so the wider set is applied when filtering content submitted by unauthenticated users as well, allowing them to store markup which the Kubio AI Page Builder WordPress plugin before 2.9.3's own script later executes in the browser of any visitor, or of an administrator reviewing the still-unapproved submission.
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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