high
7.5
CWE
674
Advisory Published
CVE Published
Updated

CVE-2021-42717

First published: Tue Dec 07 2021(Updated: )

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.

Credit: cve@mitre.org cve@mitre.org cve@mitre.org

Affected SoftwareAffected VersionHow to fix
ubuntu/modsecurity-apache<2.9.2-1ubuntu0.1~
2.9.2-1ubuntu0.1~
ubuntu/modsecurity-apache<2.9.3-1ubuntu0.1
2.9.3-1ubuntu0.1
ubuntu/modsecurity-apache<2.9.0-1ubuntu0.1~
2.9.0-1ubuntu0.1~
ubuntu/modsecurity-apache<2.9.7-1
2.9.7-1
debian/modsecurity<=3.0.3-1+deb10u2<=3.0.4-2
3.0.9-1+deb12u1
3.0.12-1
debian/modsecurity-apache
2.9.3-1+deb10u1
2.9.3-1+deb10u2
2.9.3-3+deb11u2
2.9.3-3+deb11u1
2.9.7-1
Trustwave ModSecurity>=2.0.0<2.9.5
Trustwave ModSecurity>=3.0.0<3.0.6
F5 NGINX ModSecurity WAF=r24
F5 NGINX ModSecurity WAF=r25
Debian Debian Linux=9.0
Debian Debian Linux=10.0
Debian Debian Linux=11.0
Oracle HTTP Server=12.2.1.3.0
Oracle HTTP Server=12.2.1.4.0
Oracle Sun ZFS Storage Appliance Kit=8.8

Remedy

https://www.oracle.com/security-alerts/cpuapr2022.html

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Reference Links

Parent vulnerabilities

(Appears in the following advisories)

Frequently Asked Questions

  • What is CVE-2021-42717?

    CVE-2021-42717 is a vulnerability in ModSecurity 3.x through 3.0.5 that mishandles excessively nested JSON objects.

  • How does CVE-2021-42717 affect ModSecurity?

    CVE-2021-42717 can result in the web server being unable to service legitimate requests due to crafted JSON objects with excessive nesting.

  • What is the severity of CVE-2021-42717?

    The severity of CVE-2021-42717 is moderate.

  • How can I mitigate CVE-2021-42717?

    To mitigate CVE-2021-42717, update ModSecurity to version 2.9.2-1ubuntu0.1~ or apply the appropriate remedy provided by your distribution.

  • Where can I find more information about CVE-2021-42717?

    More information about CVE-2021-42717 can be found on the CVE details page and the ModSecurity GitHub issue page.

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