CVE-2026-25863
CWE-1284Published: May 4, 2026· Updated: May 5, 2026
Official Description
Conditional Fields for Contact Form 7 WordPress plugin through version 2.6.7 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.
Technical Analysis
CVE-2026-25863 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.
CVSS v3.1 Vector Breakdown
Affected Vendors & Products
Exploit & PoC Resources
All References (2)
Quick Facts
Related CVEs (CWE-1284)
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-25863 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts