Auth bypass in Owasp Modsecurity Core Rule Set
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).
Vulnerability class: Broken Access Control
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.012 (68.5th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 69th percentile — 68.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: +0.000
Affected products
- Owasp Modsecurity Core Rule Set — versions 3.0.x, 3.1.x, unspecified
- Owasp Modsecurity Core Rule Set
- Debian Linux — versions 10.0
- Fedoraproject Fedora — versions 35, 36, 37
Weakness classification (CWE)
Public proof-of-concept exploits
References
- coreruleset.org/20220919/crs-version-3-3-3-and-3-2-2-covering-several-cves/ (Patch, Vendor Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- lists.debian.org/debian-lts-announce/2023/01/msg00033.html (mailing-list, Mailing List, Third Party Advisory)
- security.gentoo.org/glsa/202305-25 (vendor-advisory)
- af854a3a-2127-422b-91ae-364da2661108
Frequently asked questions
- What is CVE-2022-39956?
- CVE-2022-39956 is a high-severity vulnerability in Owasp Modsecurity Core Rule Set, classified under Incorrect Authorization. CVSS score: 7.3/10. Published 2022-09-20.
- How severe is CVE-2022-39956?
- High severity. CVSS v3 base score is 7.3 out of 10.
- Is CVE-2022-39956 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.