CVE-2021-42717
HIGH7.5EPSS 2.0%modsecurity-apache - security update
Published: 12/7/2021Modified: 4/28/2026
Description
ModSecurity 3.x through 3.0.5 mishandles excessively nested JSON objects. Crafted JSON objects with nesting tens-of-thousands deep could result in the web server being unable to service legitimate requests. Even a moderately large (e.g., 300KB) HTTP request can occupy one of the limited NGINX worker processes for minutes and consume almost all of the available CPU on the machine. Modsecurity 2 is similarly vulnerable: the affected versions include 2.8.0 through 2.9.4.
Affected packages (6)
- Bitnami/modsecurity>= 2.0.0, < 2.9.5
- Bitnami/modsecurity2>= 2.0.0, < 2.9.5
- Debian/modsecurityfrom 0
- Debian/modsecurity-apachefrom 0, < 2.9.3-3+deb11u1
- Debian/modsecurity-apachefrom 0, < 2.9.1-2+deb9u1
- Debian/modsecurity-apachefrom 0, < 2.9.3-1+deb10u1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
References (6)
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2021-42717
- WEBhttps://lists.debian.org/debian-lts-announce/2022/05/msg00042.html
- WEBhttps://nvd.nist.gov/vuln/detail/CVE-2021-42717
- WEBhttps://www.debian.org/security/2021/dsa-5023
- WEBhttps://www.oracle.com/security-alerts/cpuapr2022.html
- WEBhttps://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/modsecurity-dos-vulnerability-in-json-parsing-cve-2021-42717/