title: Response body bypass in OWASP ModSecurity Core Rule Set via a specialy crafted charset in the HTTP Accept header
description: The OWASP ModSecurity Core Rule Set (CRS) is affected by a response body bypass. A client can issue an HTTP Accept header field containing an optional "charset" parameter in order to receive the response in an encoded form. Depending on the "charset", this response can not be decoded by the web application firewall. A restricted resource, access to which would ordinarily be detected, may therefore bypass detection. The legacy CRS versions 3.0.x and 3.1.x are affected, as well as the currently supported versions 3.2.1 and 3.3.2. Integrators and users are advised to upgrade to 3.2.2 and 3.3.3 respectively.
problem types: CWE-693: Protection Mechanism Failure
affected:
{
vendor: OWASP
product: ModSecurity Core Rule Set
versions:
version: 3.0.x, status: affected
version: 3.1.x, status: affected
version: unspecified, lessThanOrEqual: 3.2.1, status: affected, versionType: custom
version: unspecified, lessThanOrEqual: 3.3.2, status: affected, versionType: custom
}
metrics:
cvssV3_1: [
version: 3.1
vectorString: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
attackVector: NETWORK
attackComplexity: LOW
privilegesRequired: NONE
userInteraction: NONE
scope: UNCHANGED
confidentialityImpact: LOW
integrityImpact: LOW
availabilityImpact: LOW
baseScore: 7.3
baseSeverity: HIGH
]
solutions: upgrade to 3.2.2 or 3.3.3