#VU72087 Input validation error in OWASP ModSecurity Core Rule Set (CRS) - CVE-2022-39955

Vulnerability identifier: #VU72087

Vulnerability risk: Medium

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2022-39955

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
OWASP ModSecurity Core Rule Set (CRS)
Server applications / Other server solutions

Vendor: OWASP

Description

The vulnerability allows a remote attacker to bypass filtration rules.

The vulnerability exists due to insufficient validation of user-supplied input when parsing HTTP Content-Type header field that indicates multiple character encoding schemes. A remote attacker send a specially crafted HTTP request and bypass the configurable CRS Content-Type header "charset" allow list.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

OWASP ModSecurity Core Rule Set (CRS): 3.2.0 - 3.2.2, 3.3.0 - 3.3.3

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External links
https://coreruleset.org/20220919/crs-version-3-3-3-and-3-2-2-covering-several-cves/

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.