What’s Vulnerable › Vulnerabilities
CVE-2026-86813: MetForm < 4.1.9 - Unauthenticated Email Header Injection via Notification Reply-To
- Severity: medium (CVSS 4.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.2% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-09-11 · updated 2026-09-11
- Weakness: CWE-93
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.
Affected products
- MetForm: before 4.1.9 — fixed in 4.1.9
How to fix
Upgrade to a fixed version: MetForm 4.1.9. Check the vendor advisory for mitigations.
References
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