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.
References7
- downloads.wordpress.org/plugin/ultimate-addons-for-contact-form…
- plugins.trac.wordpress.org/browser/ultimate-addons-for-contact-…
- plugins.trac.wordpress.org/browser/ultimate-addons-for-contact-…
- plugins.trac.wordpress.org/browser/ultimate-addons-for-contact-…
- plugins.trac.wordpress.org/browser/ultimate-addons-for-contact-…
- plugins.trac.wordpress.org/changeset/3738548/ultimate-addons-fo…
- www.wordfence.com/threat-intel/vulnerabilities/id/29b9d978-f8b0…
Metrics
- CVSS 3.1
-
7.2
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N - EPSS — exploit probability
- 0% percentile: 18 · as of 10 November 2026
- CWE
- CWE-79
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.