← Back to CVEs

CVE-2021-42717

HIGH

7.5

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.

CVE Details

CVSS v3.1 Score7.5

SeverityHIGH

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

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published12/7/2021

Last Modified7/3/2025

Sourcenvd

Honeypot Sightings0

Affected Products

debian:debian_linuxf5:nginx_modsecurity_waforacle:http_serveroracle:zfs_storage_appliance_kitowasp:modsecuritytrustwave:modsecurity

Weaknesses (CWE)

CWE-674

References

https://lists.debian.org/debian-lts-announce/2022/05/msg00042.html(cve@mitre.org)

https://www.debian.org/security/2021/dsa-5023(cve@mitre.org)

https://www.oracle.com/security-alerts/cpuapr2022.html(cve@mitre.org)

https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/modsecurity-dos-vulnerability-in-json-parsing-cve-2021-42717/(cve@mitre.org)

https://lists.debian.org/debian-lts-announce/2022/05/msg00042.html(af854a3a-2127-422b-91ae-364da2661108)

https://www.debian.org/security/2021/dsa-5023(af854a3a-2127-422b-91ae-364da2661108)

https://www.oracle.com/security-alerts/cpuapr2022.html(af854a3a-2127-422b-91ae-364da2661108)

https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/modsecurity-dos-vulnerability-in-json-parsing-cve-2021-42717/(af854a3a-2127-422b-91ae-364da2661108)

IOC Correlations

No correlations recorded

This product uses data from the NVD API but is not endorsed or certified by the NVD.