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.
The exploit chains six security issues into a zero-click attack. The flaws are collectively tracked as CVE-2026-18431 and received a 9.8 critical severity score.
The attack comprises exploits for authorization, input-validation, trust-boundary, and file-handling weaknesses, which must be executed in a specific order to enable arbitrary PHP code execution on a target server.
Hackers who successfully exploit these vulnerabilities could fully compromise websites for malicious activities ranging from planting malware and accessing databases to redirecting visitors to malicious sites or adding rogue admin accounts.
CVE-2026-18431 affects Avada versions up to 7.16 and Fusion Builder plugin versions up to 3.16, researchers at Defiant's Wordfence team say in a report on Tuesday.
