# CVE-2018-9230: Security feature bypass in n/a

> Attackers can bypass Web Application Firewall protections by sending more than 100 URI parameters, which OpenResty ignores by default.

- **Severity:** Critical 9.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 2 Apr 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-fgf7-9g3w-445r

## What is CVE-2018-9230?

CVE-2018-9230 is a critical vulnerability in n/a, published on 2 Apr 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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

Weakness: CWE-89 (Improper Neutralization of Special Elements used in an SQL Command)

## Which versions are affected by CVE-2018-9230?

It affects 1 product.


Products: Openresty Openresty.

## How do I fix CVE-2018-9230?

No fix has been published for CVE-2018-9230 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-9230 being exploited?

There is no known exploitation of CVE-2018-9230 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2026-55233](https://insights.sbomify.com/CVE-2026-55233/): OpenResty: Buffer overflow when writing PROXY protocol v2 header to upstream (high 7.5)
- [CVE-2024-39702](https://insights.sbomify.com/CVE-2024-39702/): Denial of service in n/a (medium 5.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-9230 and fix it if it is affected.

What it is: CVE-2018-9230 is a critical vulnerability in n/a, published on 2 Apr 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2018-9230 in the wild and no public exploit code.

Affected product: n/a. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2018-9230/ (Markdown: https://insights.sbomify.com/CVE-2018-9230/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-9230
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-9230
- OSV: https://osv.dev/vulnerability/CVE-2018-9230

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-9230/
Summaries are generated and may contain mistakes; the official description above is the record.