CVE-2021-42717
High
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.
SeverityHigh
CVSS7.5
Exploit probability—
Product
Owasp Modsecurity
PublishedDec 7, 2021
First seenDec 7, 2021
How to fix
Update
- owasp modsecurity3.0.6 or later
- trustwave modsecurity2.9.5 or later
Vendor advisories
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| owasp modsecurity | 3.0.0 ≤ v < 3.0.6 | 3.0.6 |
| trustwave modsecurity | 2.0.0 ≤ v < 2.9.5 | 2.9.5 |
| f5 nginx_modsecurity_waf | r24, r25 | — |
| debian debian_linux | 9.0, 10.0, 11.0 | — |
| oracle http_server | 12.2.1.3.0, 12.2.1.4.0 | — |
| oracle zfs_storage_appliance_kit | 8.8 | — |
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