Bug 2031841 (CVE-2021-42717)

Summary:	CVE-2021-42717 libmodsecurity: crafted JSON objects with nesting could result in the web server being unable to service legitimate requests
Product:	[Other] Security Response	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED UPSTREAM	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	apmukher, athmanem, dridi.boukelmoune
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
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Clone Of:		Environment:
Last Closed:	2021-12-13 15:05:12 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2031842, 2031843
Bug Blocks:

Description Guilherme de Almeida Suckevicz 2021-12-13 14:33:14 UTC

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.

Reference:
https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/modsecurity-dos-vulnerability-in-json-parsing-cve-2021-42717/

Comment 1 Guilherme de Almeida Suckevicz 2021-12-13 14:33:29 UTC

Created libmodsecurity tracking bugs for this issue:

Affects: epel-7 [bug 2031843]
Affects: fedora-all [bug 2031842]

Comment 2 Product Security DevOps Team 2021-12-13 15:05:11 UTC

This CVE Bugzilla entry is for community support informational purposes only as it does not affect a package in a commercially supported Red Hat product. Refer to the dependent bugs for status of those individual community products.