CVE-2026-25863 Conditional Fields for Contact Form 7 < 2.7.3 DoS via Uncontrolled Resource Consumption
Unauthenticated attackers can cause a denial of service by sending large integers to a REST API endpoint, exhausting server memory in the Conditional Fields for Contact Form 7 plugin.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-25863?
CVE-2026-25863 is a high-severity denial of service vulnerability in Jules Colle Conditional Fields for Contact Form 7, published on 4 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-1284
Which versions are affected by CVE-2026-25863?
How do I fix CVE-2026-25863?
No fix has been published for CVE-2026-25863 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-25863 being exploited?
There is no known exploitation of CVE-2026-25863 in the wild and no public exploit code.
Sources
Also known as GHSA-2g6f-p97f-gp43.