CVE-2026-15664

Received Received - Intake

Stored XSS in Quill Forms WordPress Plugin

Publication date: 2026-09-19

Last updated on: 2026-09-19

Assigner: Wordfence

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 Scores

EPSS Scores

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Meta Information

Published

2026-09-19

Last Modified

2026-09-19

Generated

2026-09-20

AI Q&A

2026-09-20

EPSS Evaluated

N/A

NVD

CVE-2026-15664

Affected Vendors & Products

Vendor	Product	Version / Range
quill_forms	conversational_multi_step_forms	to 5.7.1 (inc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-79	The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.

Attack-Flow Graph

Executive Summary

This vulnerability is a Stored Cross-Site Scripting (XSS) flaw in the Quill Forms WordPress plugin. It allows unauthenticated attackers to inject malicious scripts via the 'Other' value in Multiple Choice fields. The scripts execute when administrators view form entries, targeting them specifically.

Detection Guidance

This vulnerability is specific to WordPress sites using the Quill Forms plugin. To detect it, check if your WordPress site has the Quill Forms plugin installed and verify its version. If it is version 5.7.1 or lower, the site is vulnerable.

Impact Analysis

If exploited, this vulnerability could allow attackers to steal sensitive data, manipulate admin sessions, or perform actions on behalf of administrators. Users visiting infected pages may have their sessions hijacked or be redirected to malicious sites.

Compliance Impact

This vulnerability could lead to unauthorized access to personal data, violating GDPR and HIPAA requirements for data protection and confidentiality. Organizations may face legal penalties and reputational damage if exploited.

Mitigation Strategies

Immediately update the Quill Forms plugin to the latest version if available. If no update is available, consider disabling or removing the plugin until a patch is released. Regularly audit installed plugins for vulnerabilities.

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