CVE-2022-39957: Response body bypass in OWASP ModSecurity Core Rule Set via a specialy crafted charset in the HTTP Accept header
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.
Affected Software
Remediation
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Event History
Frequently Asked Questions
What is the vulnerability ID for this ModSecurity Core Rule Set (CRS) vulnerability?
The vulnerability ID for this ModSecurity Core Rule Set (CRS) vulnerability is CVE-2022-39957.
What is the severity of CVE-2022-39957?
The severity of CVE-2022-39957 is high with a severity value of 7.5.
Which software is affected by CVE-2022-39957?
The OWASP ModSecurity Core Rule Set (CRS) versions 3.0.0 to 3.2.2 and versions 3.3.0 to 3.3.3 are affected. Fedora versions 35, 36, and 37, as well as Debian Linux version 10.0, are also affected.
How can an attacker exploit this vulnerability?
An attacker can exploit this vulnerability by issuing an HTTP Accept header field containing an optional "charset" parameter to receive the response in an encoded form.
Are there any fixes or patches available for this vulnerability?
Yes, patches and updates are available for the affected software. Please refer to the provided references for more information on how to apply the fixes.