CVE-2022-39955
Partial rule set bypass in OWASP ModSecurity Core Rule Set by submitting a specially crafted HTTP Content-Type 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 partial rule set bypass by submitting a specially crafted HTTP Content-Type header field that indicates multiple character encoding schemes. A vulnerable back-end can potentially be exploited by declaring multiple Content-Type "charset" names and therefore bypassing the configurable CRS Content-Type header "charset" allow list. An encoded payload can bypass CRS detection this way and may then be decoded by the backend. 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-863 Incorrect Authorization
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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