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CVE-2022-39956

CRITICALCVSS 9.8/10EPSS 0.93%

Last modified

CVE-2022-39956 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass for HTTP multipart requests by submitting a payload that uses a character encoding scheme via the Content-Type or the deprecated Content-Transfer-Encoding multipart MIME header fields that will not be decoded and inspected by the web application firewall engine and the rule set. The multipart payload will therefore bypass detection. EPSS estimates a 0.93% chance of exploitation in the next 30 days.

Description

The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass for HTTP multipart requests by submitting a payload that uses a character encoding scheme via the Content-Type or the deprecated Content-Transfer-Encoding multipart MIME header fields that will not be decoded and inspected by the web application firewall engine and the rule set. The multipart payload will therefore bypass detection. A vulnerable backend that supports these encoding schemes can potentially be exploited. 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 upgrade to 3.2.2 and 3.3.3 respectively. The mitigation against these vulnerabilities depends on the installation of the latest ModSecurity version (v2.9.6 / v3.0.8).

Metrics

CVSS 3.1
9.8/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability
0.93%

55.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
OwaspOwasp Modsecurity Core Rule Set>= 3.0.0, < 3.2.2
OwaspOwasp Modsecurity Core Rule Set>= 3.3.0, < 3.3.3
FedoraprojectFedora35
FedoraprojectFedora36
FedoraprojectFedora37
DebianDebian Linux10.0

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2022-39956?
The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass for HTTP multipart requests by submitting a payload that uses a character encoding scheme via the Content-Type or the deprecated Content-Transfer-Encoding multipart MIME header fields that will not be decoded and inspected by the web application firewall engine and the rule set. The multipart payload will therefore bypass detection. A vulnerable backend that supports these encoding schemes can potentially be exploited. 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 upgrade to 3.2.2 and 3.3.3 respectively. The mitigation against these vulnerabilities depends on the installation of the latest ModSecurity version (v2.9.6 / v3.0.8).
How severe is CVE-2022-39956?
CVE-2022-39956 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.93% probability of exploitation in the next 30 days.
How do I fix CVE-2022-39956?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2022-39956?

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Source: NVD / NIST