Answer in brief
CVE-2026-86813 records a Medium severity (CVSS 4.8) vulnerability in MetForm < 4.1.9 - Unauthenticated Email Header Injection via Notification Reply-To. The current sources do not mark it as known exploited. The current feed maps Unknown/MetForm (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 4.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Unknown/MetForm (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Unknown/MetFormgeneric | >=0 <4.1.9 | 4.1.9 |
Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 11, 2026
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.
Quoted source text, attributed separately from HOL analysis.