ModSecurity is an open source, cross platform web application firewall (WAF) engine for Apache, IIS and Nginx. Versions prior to 2.9.10 contain a denial of service vulnerability similar to GHSA-859r-vvv8-rm8r/CVE-2025-47947. The `sanitiseArg` (and `sanitizeArg` - this is the same action but an alias) is vulnerable to adding an excessive number of arguments, thereby leading to denial of service. Version 2.9.10 fixes the issue. As a workaround, avoid using rules that contain the  `sanitiseArg` (or `sanitizeArg`) action.

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWE-1050

https://github.com/owasp-modsecurity/ModSecurity/commit/3a54ccea62d3f7151bb08cb78d60c5e90b53ca2e

https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-859r-vvv8-rm8r

https://github.com/owasp-modsecurity/ModSecurity/security/advisories/GHSA-f82j-8pp7-cw2w

https://github.com/owasp-modsecurity/ModSecurity/wiki/Reference-Manual-(v2.x)#sanitisearg