# CVE-2000-0536: Auth bypass in n/a

> Attackers can bypass access controls in xinetd when hostname-based restrictions are used and reverse DNS fails, allowing unauthorized connections.

- **Severity:** High 7.5 (`AV:N/AC:L/Au:N/C:P/I:P/A:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 13 Oct 2000
- **Updated:** 8 Aug 2024
- **Also known as:** GHSA-c22c-879v-fc62

## What is CVE-2000-0536?

CVE-2000-0536 is a high-severity authentication bypass vulnerability in n/a, published on 13 Oct 2000. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

xinetd 2.1.8.x does not properly restrict connections if hostnames are used for access control and the connecting host does not have a reverse DNS entry.

## Which versions are affected by CVE-2000-0536?

It affects 1 product.


Products: Xinetd Xinetd.

## How do I fix CVE-2000-0536?

No fix has been published for CVE-2000-0536 yet. Limit exposure of the affected software until one is available.

## Is CVE-2000-0536 being exploited?

There is no known exploitation of CVE-2000-0536 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2001-0825](https://insights.sbomify.com/CVE-2001-0825/): Memory corruption in n/a (critical 10.0)
- [CVE-2001-1389](https://insights.sbomify.com/CVE-2001-1389/): Memory corruption in n/a (high 7.5)
- [CVE-2003-0211](https://insights.sbomify.com/CVE-2003-0211/): Denial of service in n/a (medium 5.0)
- [CVE-2012-0862](https://insights.sbomify.com/CVE-2012-0862/): Auth bypass in n/a (medium 4.3)
- [CVE-2001-1322](https://insights.sbomify.com/CVE-2001-1322/): Misconfiguration in n/a (low 3.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2000-0536 and fix it if it is affected.

What it is: CVE-2000-0536 is a high-severity authentication bypass vulnerability in n/a, published on 13 Oct 2000. 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-2000-0536 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-2000-0536/ (Markdown: https://insights.sbomify.com/CVE-2000-0536/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2000-0536
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2000-0536
- OSV: https://osv.dev/vulnerability/CVE-2000-0536

---
From sbomify Insights: https://insights.sbomify.com/CVE-2000-0536/
Summaries are generated and may contain mistakes; the official description above is the record.