---
id: CVE-2026-86813
title: >-
  The MetForm WordPress plugin before 4.1.9 does not properly neutralize newline
  characters in user-submitted values that are placed into notification email
  headers, allowing unauthenticated attackers to inject additional email
  headers, su…
summary: >-
  The MetForm WordPress plugin before 4.1.9 does not properly neutralize newline
  characters in user-submitted values that are placed into notification email
  headers, allowing unauthenticated attackers to inject additional email
  headers, su…
severity: medium
cvss: 4.8
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N'
cwe:
  - CWE-93
product: MetForm
affected:
  - MetForm < 4.1.9
published: '2026-09-11'
updated: '2026-09-11'
sourceUpdated: '2026-09-11T17:35:21.440'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-86813'
references:
  - url: 'https://wpscan.com/vulnerability/afda2a26-b965-42cb-85a8-4a4d83ec026e/'
    label: contact@wpscan.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-11T12:05:38.615469Z'
ingestedAt: '2026-09-11T16:45:47.922Z'
epss: 0.00243
epssPercentile: 0.13812
---

## Overview

The MetForm WordPress plugin before 4.1.9 does not properly neutralize newline characters in user-submitted values that are placed into notification email headers, allowing unauthenticated attackers to inject additional email headers, such as Bcc, into the emails the site sends when a submitted field value is configured to populate a header.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.