Threat Intelligence / CVE / CVE-2026-18431

CVE-2026-18431 — themefusion Avada (Fusion) Builder

CVSS v3.1 9.8 (CRITICAL) · EPSS 0.6% (higher than 48.0% of all scored CVEs) · Priority 8.8/10 · Published 2026-08-26

As of 2026-08-27, CVE-2026-18431 is a CRITICAL-severity vulnerability in themefusion Avada (Fusion) Builder, CVSS v3.1 9.8, EPSS 0.6% (48.0th percentile). Threadlinqs Intelligence links 2 tracked threat campaigns to CVE-2026-18431, most recently “Five Critical WordPress Plugin/Theme Flaws (CVSS up to 10.0) Enable Site Takeover or RCE: WPMU DEV Dashboard, Avada/Fusion Builder, TranslatePress, Pods, GiveWP”.

Last updated: 2026-08-27

What is CVE-2026-18431?

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.

The record classifies CVE-2026-18431 under weakness class CWE-862. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 2 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 25 days ago.

Severity and exploitation probability

CVSS v3.1 base score
9.8 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (FIRST)
0.6% probability of exploitation in the next 30 days, higher than 48.0% of all scored CVEs
CISA KEV
Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority
8.8/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published
2026-08-26, last modified 2026-08-27

Is CVE-2026-18431 being exploited?

Weaponised exploit code for CVE-2026-18431 is publicly available. 1 public proof-of-concept repository is tracked for this identifier.

Affected products and versions

How to fix CVE-2026-18431

No vendor patch reference has been recorded for CVE-2026-18431 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

Threat activity tracking CVE-2026-18431

2 tracked threats in the Threadlinqs corpus reference CVE-2026-18431, either in the campaign’s CVE list or as an indicator on the campaign record.

Sources

Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.

Other references

Full detection coverage & IOCs for threats exploiting CVE-2026-18431 are available via the Threadlinqs MCP server (Purple tier). View plans →

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