Topcontent WordPress plugin: Unauthenticated stored Cross-Site Scripting
Summary
The Topcontent WordPress plugin up to and including version 1.2.1 does not properly authorise one of its request handlers and disables HTML sanitisation before storing submitted content. An unauthenticated attacker can publish posts containing malicious JavaScript on sites where the plugin's API key has never been configured. Visitors who open the poisoned post, typically a user-interaction step, may have scripts executed in their browser in the context of the affected site.
Affected
- Topcontent WordPress plugin, versions 0 through 1.2.1
- Affected only on sites where the API key has never been configured, according to the vulnerability description
Fixed in
Unknown. WPScan lists no known fix and no vendor advisory or fixed release was found.
Workaround
- No verified workaround is known.
- Deactivate and remove the plugin if it is not required.
- Consider a web application firewall or virtual patch as a temporary measure.
- Do not rely on a configured API key as a protection without confirmation from the vendor.
Exploitation
- CISA SSVC: exploitation none, automatable no, technical impact total.
- Not listed in CISA KEV. EPSS about 0.17%.
- VulDB reports no exploit available. Public proof of concept status is unverified.
- No known in-the-wild exploitation.
Our recommendation
- Inventory all WordPress sites to check whether the Topcontent plugin is installed.
- Remove the plugin where it is not needed.
- Where it is needed, check the API key status and review recently published posts for unexpected authors, scripts or injected HTML.
- Monitor the vendor and WPScan pages for a fixed version and update promptly once available.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- WPScan vulnerability entry CVE-2026-88903 wpscan.com
- OpenCVE CVE-2026-88903 app.opencve.io
- VulDB entry 416528 vuldb.com
- Topcontent WordPress plugin vendor page topcontent.com
- Patchstack via Vulners 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, 20:37.
Original description (NVD)
The Topcontent WordPress plugin through 1.2.1 does not properly authorise one of its request handlers and disables HTML sanitisation before storing the submitted content, allowing unauthenticated attackers to publish arbitrary posts containing malicious JavaScript on any site where its API key has never been configured.
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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