CVE-2026-18431 Avada <= 7.16 and Fusion Builder <= 3.16 - Unauthenticated Remote Code Execution via Arbitrary File Write
Unauthenticated attackers can write arbitrary files to the server, leading to remote code execution and full site compromise in Avada and Fusion Builder.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-18431?
CVE-2026-18431 is a critical vulnerability in ThemeFusion Avada (Fusion) Builder, published on 26 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The Avada theme for WordPress is vulnerable to Arbitrary File Write in all versions up to, and including, 7.16 when the Fusion Builder plugin is installed and active in versions up to, and including, 3.16. This is due to a chain of authorization and input validation weaknesses across the two components that makes it possible for unauthenticated attackers to write attacker-controlled files to the server. This can be used to create and execute arbitrary PHP files, resulting in remote code execution and complete site compromise. Successful exploitation requires both Avada and Fusion Builder to be installed and active, as well as certain administrator-authored content to be present.
Weakness: CWE-862
Which versions are affected by CVE-2026-18431?
How do I fix CVE-2026-18431?
No fix has been published for CVE-2026-18431 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-18431 being exploited?
There is no known exploitation of CVE-2026-18431 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as GHSA-hm9x-g2wh-6xw7.