FC United WordPress theme: Unauthenticated PHP Object Injection
Summary
The FC United WordPress theme by AxiomThemes, in versions 1.1.1 and older, contains an unauthenticated PHP Object Injection flaw (CWE-502). An unauthenticated remote attacker can supply crafted data that the site processes as a PHP object, which can allow manipulation of application logic and harmful actions on the server. Patchstack rates the issue as high priority with a CVSS score of 9.8. No fixed version has been confirmed.
Affected
- FC United theme (WordPress), versions <= 1.1.1
- Vendor: AxiomThemes
Fixed in
Unknown.
- No official patch was reported at the time of review.
Workaround
- Remove or deactivate the theme on sites where it is not actively needed.
- If it must remain online, ask the hosting provider or a WAF/virtual-patching service whether a rule covers this Patchstack entry. No vendor-published workaround was found.
- Verify backups and review web-server logs for unusual requests, unknown files and unknown admin accounts.
Exploitation
- No known in-the-wild exploitation in the sources reviewed. The CISA SSVC assessment lists Exploitation: none, Automatable: yes, Technical Impact: total.
- Public proof of concept: unknown. No PoC was found, but this does not rule one out.
- The record is not listed in CISA KEV according to the sources reviewed.
Our recommendation
- Inventory all WordPress sites and check whether the FC United theme is installed and which version is active.
- Remove or isolate the theme where it is not required.
- Check the Patchstack advisory and the AxiomThemes changelog regularly and update as soon as a fixed version is confirmed.
- Monitor web-server logs for suspicious requests and check sites for unknown files or admin accounts.
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Patchstack advisory: WordPress FC United theme <= 1.1.1 PHP Object Injection patchstack.com
- OpenCVE: CVE-2026-66565 app.opencve.io
- HOL Guard: CVE-2026-66565 WordPress FC United theme hol.org
- Strix AI: CVE-2026-66565 www.strix.ai
- Vulners: RAPID7:CVE-2026-66565 vulners.com
- ThemeForest: FC United Football Soccer WordPress Sports Theme themeforest.net
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 30 Oct 2026, 19:30.
Original description (NVD)
Unauthenticated PHP Object Injection in FC United <= 1.1.1 versions.
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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