Email Header Injection in MetForm Plugin for WordPress
CVE-2026-86813

4.8MEDIUM

Key Information:

Vendor

WordPress
Status
Metform
Vendor
CVE Published:
11 September 2026

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2026-86813?

The MetForm plugin for WordPress versions prior to 4.1.9 contains a vulnerability that fails to neutralize newline characters in user-submitted values. This flaw permits unauthenticated attackers to inject additional headers, such as Bcc, into outgoing notification emails. This can result in unauthorized exposure of email addresses and compromise the integrity of user communication, which emphasizes the critical need for protecting user input within web applications.

Affected Version(s)

MetForm 0 < 4.1.9

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2026-86813 - Proof of Concept

References

https://wpscan.com/vulnerability/afda2a26-b965-42cb-85a8-...
exploitvdb-entrytechnical-description

CVSS V3.1

Score:
4.8
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Artus KG
WPScan
.