Full Report
A critical vulnerability chain in the popular Avada theme for WordPress can be exploited by an unauthenticated attacker to execute arbitrary PHP code on the server. [...]
Analysis Summary
# Vulnerability: Avada Theme & Fusion Builder RCE Chain
## CVE Details
- **CVE ID:** CVE-2026-18431
- **CVSS Score:** 9.8 (Critical)
- **CWE:** Multiple (Authorization Bypass, Input Validation, Trust Boundary Violation, File-Handling Weaknesses)
## Affected Systems
- **Products:** Avada Theme and Fusion Builder Plugin
- **Versions:**
- Avada Theme versions up to and including 7.16
- Fusion Builder Plugin versions up to and including 3.16
- **Configurations:** The vulnerability requires **both** the Avada theme and the Fusion Builder plugin to be active on the target website simultaneously.
## Vulnerability Description
CVE-2026-18431 is a complex "zero-click" vulnerability chain consisting of six distinct security flaws. By chaining these issues, an unauthenticated attacker can manipulate public requests to influence internal trusted states and bypass administrative protections. The chain culminates in a file-handling restriction bypass, allowing the attacker to write arbitrary files to the server, ultimately leading to Remote Code Execution (RCE).
## Exploitation
- **Status:** PoC developed by researchers (Wordfence Argus framework); no confirmed exploitation in the wild at the time of the report.
- **Complexity:** Medium (Requires a specific 6-step sequence of requests).
- **Attack Vector:** Network (Remote, unauthenticated).
## Impact
- **Confidentiality:** High (Full access to databases and sensitive site information).
- **Integrity:** High (Ability to plant malware, add rogue admin accounts, or modify site content).
- **Availability:** High (Potential for full server takeover or site deletion).
## Remediation
### Patches
Update to the following versions immediately:
- **Avada Theme:** Version 7.16.1 or later.
- **Fusion Builder Plugin:** Version 3.16.1 or later.
### Workarounds
No specific workarounds (such as configuration changes) have been provided. The primary remediation is a full update of the theme and its associated builder plugin.
## Detection
- **Indicators of Compromise:**
- Presence of unauthorized PHP files in WordPress directories.
- Creation of unexpected administrative accounts.
- Unusual logs showing unauthenticated requests hitting privileged or administrative components (Steps 2 and 3 of the attack chain).
- **Detection methods and tools:** Wordfence and other WordPress-specific security scanners may be updated to detect the specific signatures of this chain.
## References
- **Vendor Advisory:** ThemeFusion (Avada) Official Release Notes
- **Wordfence Report:** hxxps[://]www[.]wordfence[.]com/blog/2026/08/wordfence-argus-finds-complex-6-step-critical-rce-in-avada-theme-with-1-million-sales/
- **BleepingComputer Article:** hxxps[://]www[.]bleepingcomputer[.]com/news/security/critical-avada-wordpress-theme-flaw-enables-zero-click-rce/