security-advisories@github.com reports:
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.