# CVE-2022-39956: modsecurity-crs: The OWASP ModSecurity Core Rule Set (CRS) is affected by a partial rule set bypass for HTTP multipart requests by sub...

CVE-2022-39956 is fixed in modsecurity-crs on 1 platform, first by DEBIAN-CVE-2022-39956, released September 20, 2022. It is not reported as exploited. Patch Radar priority: Urgent.

- Web page: https://patchblox.com/security/cve/CVE-2022-39956
- Priority: Urgent
- CVSS: 9.8 (critical)
- EPSS: 0.0121
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 20, 2022

## 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).

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | modsecurity-crs Debian 12.15 (bookworm) | 3.3.4-1 | [DEBIAN-CVE-2022-39956](https://patchblox.com/security/data/fix/linux/debian-cve-2022-39956.md) | Sep 20, 2022 |
| Linux | modsecurity-crs Debian 13.5 (trixie) | 3.3.4-1 | [DEBIAN-CVE-2022-39956](https://patchblox.com/security/data/fix/linux/debian-cve-2022-39956.md) | Sep 20, 2022 |
| Linux | modsecurity-crs Debian 14 | 3.3.4-1 | [DEBIAN-CVE-2022-39956](https://patchblox.com/security/data/fix/linux/debian-cve-2022-39956.md) | Sep 20, 2022 |

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