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Vulnerability record · CVE-2026-15664 · published 19 September 2026

CVE-2026-15664: Cross-site scripting vulnerability

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.

7.2 CVSS 3.1 High EPSS 0.39% · top 69.9% CWE-79 · Cross-site scripting Deferred
7.2CVSS 3.1 base score
0.39%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
14References
21 Sep 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

References

LinkTags
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/5.6.1/includes/blocks/multiple-choice/class-multiple-choice-b
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/rest-api/controllers/v1/class-rest-entry-contr
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/blocks/multiple-choice/class-multiple-choice-b
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/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/rest-api/controllers/v1/class-rest-entry-contr
https://plugins.trac.wordpress.org/changeset?reponame=&old=3663009%40quillforms&new=3663009%40quillforms
https://www.wordfence.com/threat-intel/vulnerabilities/id/1261881f-7a04-47fb-8176-6a9ac2088f8d?source=cve

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Source: NIST National Vulnerability Database (record CVE-2026-15664), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.