CVE-2022-39957 HIGH

CVE-2022-39957: Response body bypass in OWASP ModSecurity Core Rule Set via a specialy crafted charset in the HTTP Accept header

Vendor Owasp
Product ModSecurity Core Rule Set
Weakness CWE-693
Published September 20, 2022
Last update November 3, 2025

CVSS base score

7.3/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality Low
Integrity Low

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

September 20, 2022 CVE published
November 3, 2025 Record updated