Vulnerability in Owasp Modsecurity Core Rule Set

CVE-2022-39957

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.

EPSS: 0.008 (55.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2022-39957?
CVE-2022-39957 is a high-severity vulnerability in Owasp Modsecurity Core Rule Set, classified under Protection Mechanism Failure. CVSS score: 7.3/10. Published 2022-09-20.
How severe is CVE-2022-39957?
High severity. CVSS v3 base score is 7.3 out of 10.
Is CVE-2022-39957 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.