CVE-2022-39957
Response body bypass in OWASP ModSecurity Core Rule Set via a specialy crafted charset in the HTTP Accept header
- State
- Published
- Severity
- 7.3 High
- Published
- Sep 20, 2022
- Updated
- Nov 3, 2025
- Reserved
- Sep 5, 2022
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.3 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L | NCSC.ch |
Weaknesses
- CWE-693 Protection Mechanism Failure
Affected Products
| Product | Versions |
|---|---|
ModSecurity Core Rule SetOWASP |
|
References
- https://coreruleset.org/20220919/crs-version-3-3-3-and-3-2-2-covering-several-cves/
- FEDORA-2022-90708b46e3vendor-advisory
- FEDORA-2022-85a85c84b3vendor-advisory
- FEDORA-2022-1fd73a5285vendor-advisory
- [debian-lts-announce] 20230130 [SECURITY] [DLA 3293-1] modsecurity-crs security updatemailing-list
- GLSA-202305-25vendor-advisory
- https://lists.debian.org/debian-lts-announce/2025/08/msg00004.html
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