Vulnerability · Published Sep 19, 2026 · Assigned by Wordfence
CVE-2026-15664Quill Forms | Conversational Multi Step Forms, Surveys & quizzes <= 5.7.1 - Unauthenticated Stored Cross-Site Scripting via Multiple Choice 'Other' Value
High 7.2
In plain English
A high-severity cross-site scripting in Quill Forms | Conversational Multi Step Forms, Surveys & quizzes from mdmag. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities).
Official description
The Quill Forms | Conversational Multi Step Forms, Surveys & quizzes plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Multiple Choice 'Other' Value in all versions up to, and including, 5.7.1 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 injected script executes in the context of the WordPress admin results view, making administrators the primary target when reviewing submitted form entries.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| mdmag | Quill Forms | Conversational Multi Step Forms, Surveys & quizzes | 0 – through 5.7.1 |
Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N
References
- https://www.wordfence.com/threat-intel/vulnerabilities/id/1261881f-7a04-47fb-8176-6a9ac2088f8d?source=cve
- https://plugins.trac.wordpress.org/browser/quillforms/tags/5.6.1/includes/class-form-submission.php#L111
- https://plugins.trac.wordpress.org/browser/quillforms/tags/5.6.1/includes/class-form-submission.php#L194
- https://plugins.trac.wordpress.org/browser/quillforms/tags/5.6.1/includes/class-form-submission.php#L262
- https://plugins.trac.wordpress.org/browser/quillforms/tags/5.6.1/includes/abstracts/class-block-type.php#L402
- https://plugins.trac.wordpress.org/browser/quillforms/tags/5.7.0/includes/blocks/multiple-choice/class-multiple-choice-block.php#L199
- https://plugins.trac.wordpress.org/browser/quillforms/tags/5.7.0/includes/class-form-submission.php#L194
- https://plugins.trac.wordpress.org/browser/quillforms/tags/5.7.0/includes/class-form-submission.php#L262
- https://plugins.trac.wordpress.org/browser/quillforms/tags/5.7.0/includes/abstracts/class-block-type.php#L402
- https://plugins.trac.wordpress.org/browser/quillforms/tags/5.7.0/includes/class-form-submission.php#L111
- https://plugins.trac.wordpress.org/browser/quillforms/tags/5.7.0/includes/rest-api/controllers/v1/class-rest-entry-controller.php#L191
- https://plugins.trac.wordpress.org/browser/quillforms/tags/5.6.1/includes/blocks/multiple-choice/class-multiple-choice-block.php#L199
- https://plugins.trac.wordpress.org/browser/quillforms/tags/5.6.1/includes/rest-api/controllers/v1/class-rest-entry-controller.php#L191
- https://plugins.trac.wordpress.org/changeset?reponame=&old=3663009%40quillforms&new=3663009%40quillforms