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CVE-2021-42717

Published: Dec 7, 2021Updated: Jul 3, 2025 Sources: CVE List NVD BDUCWE-674
7.5HIGH
NVD MITRE
EPSS Score
3.2%
Top 13.4%
CISA KEV
Not in KEV
Exploits
1 Known
Remediation
Patch Available
Self-Check
OpenVAS

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-674

Affected Products

oracle
commercial·USaka oracle corp.
http serverOn-premWeb App
Web & CMS Plugins
zfs storage appliance kitOn-premDatabase
Databases / data-warehouse-analytics
owasp
oss-project·USaka modsecurity-crs, modsecurity, owasp modsecurity core rule set
modsecurityMixed
Networking Infrastructure / firewall
trustwave
commercial·US
modsecurityMixed
Security Products / vuln-mgmt-scanner
f5
commercial·US
nginx modsecurity wafOn-premSecurity Product
Networking Infrastructure / firewall
debian
oss-project·GBaka debian gnu/linux
debian linuxOn-premOS
Operating Systems / linux-distro
Сообщество свободного программного обеспечения
oss-projectaka fsf
Debian GNU/LinuxOn-premOS
Operating Systems / linux-distro
and 2 more affected products View all →

Exploitability

1 exploit source identified

Exploit details including PoC links, Metasploit modules, and scanner templates are available after registration.

View exploit details
Official Patch Available
Workaround Available
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Attack Graph

Products CVE Techniques Tactics

Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.

MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

https://www.debian.org/security/2021/dsa-5023
debian.org
https://www.oracle.com/security-alerts/cpuapr2022.html
oracle.com
https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/modsecurity-dos-vulnerability-in-json-parsing-cve-2021-42717/
trustwave.com
and 4 more references View all →
News mentions
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