High-severity RCE (CVSS 9.8) in a widely used WordPress theme/plugin combo that can enable full site takeover across many public websites.
CVE-2026-18431
Unauthenticated arbitrary file write in Avada+Fusion Builder enabling RCE and full site takeover.
WAF coverage: Missing authorization.
Also consider: patch
Is CVE-2026-18431 being exploited?
Not confirmed. CVE-2026-18431 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.64% probability of exploitation in the next 30 days.
How severe is CVE-2026-18431?
CVE-2026-18431 is rated Critical. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-18431?
Yes. A fix has been recorded for CVE-2026-18431. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-18431 affect?
CVE-2026-18431 affects Avada WordPress theme <= 7.16, Fusion Builder plugin <= 3.16, WordPress sites with both installed and active. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-18431?
Update Avada >7.16 and Fusion Builder >3.16; disable/remove Fusion Builder if possible and scan for webshells.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Unauthenticated attackers can write PHP files, achieve remote code execution, and fully compromise WordPress sites.
Immediate action required
- affected<= 3.16
- affected<= 7.16
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.