ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Versions up to and including 2.9.8 are vulnerable to denial of service in one special case (in stable released versions): when the payload's content type is `application/json`, and there is at least one rule which does a `sanitiseMatchedBytes` action. A patch is available at pull request 3389 and expected to be part of version 2.9.9. No known workarounds are available.
CVE ID: CVE-2025-47947
CVSS Base Severity: HIGH
CVSS Base Score: 7.5
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Vendor: owasp-modsecurity
Product: ModSecurity
EPSS Score: 0.08% (probability of being exploited)
EPSS Percentile: 24.25% (scored less or equal to compared to others)
EPSS Date: 2025-06-15 (when was this score calculated)