Vulnerability · Published Oct 16, 2026 · Assigned by Wordfence

CVE-2026-103999Ultra Addons for Contact Form 7 <= 3.5.54 - Unauthenticated Stored Cross-Site Scripting via File Upload

High 7.2

In plain English

A high-severity cross-site scripting in Ultra Addons for Contact Form 7 from themefic. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 18% of all known vulnerabilities).

Severity (CVSS 3.1)7.2High

Exploit odds (30 days)0.3%top 82.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

The Ultra Addons for Contact Form 7 plugin for WordPress is vulnerable to Stored Cross-Site Scripting via File Upload in all versions up to, and including, 3.5.54 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. The extension blocklist gatekeeper is bypassed by uploading text-type files (.txt, .csv, .vtt, .srt, .asc) whose contents begin with an HTML payload such as '<BODY onload=…>', as the check classifies these files as text/plain without inspecting their byte content.

Affected products (as reported)

Vendor	Product	Versions
themefic	Ultra Addons for Contact Form 7	0 – through 3.5.54

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

In plain English

Official description

Affected products (as reported)

References