CVE-2026-103999

7.2High

Published 16 Oct 2026 · NVD status: Deferred · AI triage by gemini-3.8-flash

7.2High

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None
Impact: Limited impact
Weakness: CWE-79

Impact

Unauthenticated remote attackers can execute malicious scripts in the browsers of users or admins viewing submitted forms. They only need access to a public form that accepts file uploads.

Root cause

The file upload handler relies on file extension blocklists and MIME checks without inspecting file content, allowing HTML payloads disguised as text files to be stored and rendered without escaping.

Affected systems

Ultra Addons for Contact Form 7 (ultimate-addons-for-contact-form-7) up to and including version 3.5.54

CVSS v3.1 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Fix & remediation

Upgrade to a version past 3.5.54 once available, or deactivate the plugin immediately if patching is not yet possible.

shell

$ wp plugin update ultimate-addons-for-contact-form-7 || wp plugin deactivate ultimate-addons-for-contact-form-7

AI-suggested. Run it in staging first and check it against the vendor advisory. Why?

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NVD 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.

References

Source: nvd.nist.gov/vuln/detail/CVE-2026-103999