CVE-2026-86813

MetForm < 4.1.9 - Unauthenticated Email Header Injection via Notification Reply-To

Published Sep 11, 2026 CVSS 3.1 · 4.8 Medium EPSS < 1% KEV · Not listed
Description
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

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Wordpress-extensions
Wordpress-extensions metform
Vendors & Products Wordpress-extensions
Wordpress-extensions metform
Type Values Removed Values Added
Weaknesses CWE-20
CWE-543
Type Values Removed Values Added
Weaknesses CWE-20
CWE-543
Type Values Removed Values Added
Weaknesses CWE-93
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Title MetForm < 4.1.9 - Unauthenticated Email Header Injection via Notification Reply-To
References
Metrics cvssV3_1

{'score': 4.8, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
WPScan
Published
Updated
Sep 11, 2026, 12:06 PM
Reserved
Sep 8, 2026, 1:37 PM
Status
Deferred
Published
Sep 11, 2026, 11:16 AM
Modified
Sep 11, 2026, 5:35 PM