What’s Vulnerable › Vulnerabilities

CVE-2018-9230

• Severity: critical (CVSS 9.8 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 13.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2018-04-02 · updated 2026-06-17
• Weakness: CWE-89

Description

In OpenResty through 1.13.6.1, URI parameters are obtained using the ngx.req.get_uri_args and ngx.req.get_post_args functions that ignore parameters beyond the hundredth one, which might allow remote attackers to bypass intended access restrictions or interfere with certain Web Application Firewall (ngx_lua_waf or X-WAF) products. NOTE: the vendor has reported that 100 parameters is an intentional default setting, but is adjustable within the API. The vendor's position is that a security-relevant misuse of the API by a WAF product is a vulnerability in the WAF product, not a vulnerability in OpenResty

Affected products

• openresty: before 1.13.6.1 — fixed in 1.13.6.1

How to fix

Upgrade to a fixed version: openresty 1.13.6.1. Check the vendor advisory for mitigations.

References

• https://github.com/Bypass007/vuln/blob/master/OpenResty/Uri%20parameter%20overflow%20in%20Openresty.md
• https://openresty.org/en/changelog-1013006.html
• https://github.com/Bypass007/vuln/blob/master/OpenResty/Uri%20parameter%20overflow%20in%20Openresty.md
• https://openresty.org/en/changelog-1013006.html

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