CVE-2022-39957
The OWASP ModSecurity Core Rule Set (CRS) is affected by a response body bypass.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.82%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 0.82% probability · 55th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-693, CWE-116
- Affected
- owasp/owasp modsecurity core rule set · fedoraproject/fedora · debian/debian linux
- Source
- vulnerability@ncsc.ch
References
- https://coreruleset.org/20220919/crs-version-3-3-3-and-3-2-2-covering-several-cves/Patch, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2023/01/msg00033.htmlMailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HL2L2GF7GOCWPMJZDUE5OXDSXHGG3XUJ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PD56EAYNGB6E6QQH62LAYCONOP6OH5DZ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YPQ6CCMX3MU4A7MTCGQJA7VMJW3IQDXV/
- https://security.gentoo.org/glsa/202305-25
- https://coreruleset.org/20220919/crs-version-3-3-3-and-3-2-2-covering-several-cves/Patch, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2023/01/msg00033.htmlMailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2025/08/msg00004.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HL2L2GF7GOCWPMJZDUE5OXDSXHGG3XUJ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PD56EAYNGB6E6QQH62LAYCONOP6OH5DZ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YPQ6CCMX3MU4A7MTCGQJA7VMJW3IQDXV/
- https://security.gentoo.org/glsa/202305-25
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.