Descriptioncoreruleset (aka OWASP ModSecurity Core Rule Set) through 3.3.4 does not detect multiple Content-Type request headers on some platforms. This might allow attackers to bypass a WAF with a crafted payload, aka "Content-Type confusion" between the WAF and the backend application. This occurs when the web application relies on only the last Content-Type header. Other platforms may reject the additional Content-Type header or merge conflicting headers, leading to detection as a malformed header.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1041109

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
modsecurity-crs (PTS)buster3.1.0-1+deb10u2vulnerable
buster (security)3.2.3-0+deb10u3vulnerable
sid, trixie3.3.5-2fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs


[bookworm] - modsecurity-crs <no-dsa> (Minor issue)
[bullseye] - modsecurity-crs <no-dsa> (Minor issue)
[buster] - modsecurity-crs <postponed> (Minor issue)

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