CVE-2021-42717
What it is
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.
At a glance
- Exploitability
- Can be exploited over the network without logging in. High risk of service disruption.
- Exploit odds
- 3.2% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 3.2% in the next 30 days (EPSS).
- Severity: 7.5 HIGH (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 3.2% · EPSS, next 30 days
- Weakness
- CWE-674
- Record status
- Modified
Affected
- Owasp Modsecurity < 3.0.6
- Trustwave Modsecurity < 2.9.5
- f5 nginx Modsecurity Waf r24
- f5 nginx Modsecurity Waf r25
- Debian Linux 9.0
- Debian Linux 10.0
- Debian Linux 11.0
- Oracle Http Server 12.2.1.3.0
Attack profile CVSS 3.1 · 7.5
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2021-42717.md and follow it. Check whether this project is affected by CVE-2021-42717. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/modsecurity-dos-vulnerability-in-json-parsing-cve-2021-42717/
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/modsecurity-dos-vulnerability-in-json-parsing-cve-2021-42717/
References
- https://lists.debian.org/debian-lts-announce/2022/05/msg00042.html
- https://www.debian.org/security/2021/dsa-5023
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/modsecurity-dos-vulnerability-in-json-parsing-cve-2021-42717/
- https://lists.debian.org/debian-lts-announce/2022/05/msg00042.html
- https://www.debian.org/security/2021/dsa-5023
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/modsecurity-dos-vulnerability-in-json-parsing-cve-2021-42717/