High severity · published Dec 7, 2021
CVE-2021-42717
ModSecurity 3.x through 3.0.5 mishandles excessively nested JSON objects
7.5
CVSS
3.2%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)3.2% · higher than 88% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
DL
Debian Linux · Debian
9.0; 10.0; 11.0 · source: NVD
HS
Http Server · Oracle
12.2.1.3.0; 12.2.1.4.0 · source: NVD
MO
Modsecurity · Owasp
3.0.0 before 3.0.6 · source: NVD
NM
Nginx Modsecurity Waf · F5
r24; r25 · source: NVD
ZS
Zfs Storage Appliance Kit · Oracle
8.8 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-42717
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-42717
Mailing List
https://lists.debian.org/debian-lts-announce/2022/05/msg00042.html
Third Party Advisory
https://www.debian.org/security/2021/dsa-5023
Patch
https://www.oracle.com/security-alerts/cpuapr2022.html
Exploit
https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/modsecurity-dos-vulnerability-in-json-parsing-cve-2021-42717/
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