CVE-2023-38199

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-07-13 · updated 2026-06-17
Weakness: CWE-843

Description

coreruleset (aka OWASP ModSecurity Core Rule Set) through 3.3.4 does not detect multiple Content-Type request headers on some platforms. This might allow attackers to bypass a WAF with a crafted payload, aka "Content-Type confusion" between the WAF and the backend application. This occurs when the web application relies on only the last Content-Type header. Other platforms may reject the additional Content-Type header or merge conflicting headers, leading to detection as a malformed header.

Affected products

OWASP Coreruleset: through 3.3.4

References

https://github.com/coreruleset/coreruleset/issues/3191
https://github.com/coreruleset/coreruleset/pull/3237
https://github.com/coreruleset/coreruleset/issues/3191
https://github.com/coreruleset/coreruleset/pull/3237

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