Bug 2031841 (CVE-2021-42717) - CVE-2021-42717 libmodsecurity: crafted JSON objects with nesting could result in the web server being unable to service legitimate requests
Summary: CVE-2021-42717 libmodsecurity: crafted JSON objects with nesting could result...
Keywords:
Status: CLOSED UPSTREAM
Alias: CVE-2021-42717
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 2031842 2031843
Blocks:
TreeView+ depends on / blocked
 
Reported: 2021-12-13 14:33 UTC by Guilherme de Almeida Suckevicz
Modified: 2022-01-06 06:32 UTC (History)
3 users (show)

Fixed In Version:
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Last Closed: 2021-12-13 15:05:12 UTC
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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.
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