# CVE-2018-5256: Missing authorization in n/a

> Unauthenticated access to the Kubernetes API proxy allows attackers to list namespaces and gather internal cluster state information.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 18 May 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-2jqj-xw9v-qv9j

## What is CVE-2018-5256?

CVE-2018-5256 is a high-severity missing authorization vulnerability in n/a, published on 18 May 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

CoreOS Tectonic 1.7.x before 1.7.9-tectonic.4 and 1.8.x before 1.8.4-tectonic.3 mounts a direct proxy to the kubernetes cluster at /api/kubernetes/ which is accessible without authentication to Tectonic and allows an attacker to directly connect to the kubernetes API server. Unauthenticated users are able to list all Namespaces through the Console, resulting in an information disclosure. Tectonic's exposure of an unauthenticated API endpoint containing information regarding the internal state of the cluster can provide an attacker with information that may assist in other attacks against the cluster. For example, an attacker may not have the permissions required to list all namespaces in the cluster but can instead leverage this vulnerability to enumerate the namespaces and then begin to check each namespace for weak authorization policies that may allow further escalation of privileges.

Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2018-5256?

It affects 1 product.


Products: Redhat Tectonic.

## How do I fix CVE-2018-5256?

No fix has been published for CVE-2018-5256 yet. Limit exposure of the affected software until one is available.

## Is CVE-2018-5256 being exploited?

There is no known exploitation of CVE-2018-5256 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2018-9090](https://insights.sbomify.com/CVE-2018-9090/): Cross-site scripting in n/a (medium 6.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-5256 and fix it if it is affected.

What it is: CVE-2018-5256 is a high-severity missing authorization vulnerability in n/a, published on 18 May 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-2018-5256 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-2018-5256/ (Markdown: https://insights.sbomify.com/CVE-2018-5256/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-5256
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-5256
- OSV: https://osv.dev/vulnerability/CVE-2018-5256

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-5256/
Summaries are generated and may contain mistakes; the official description above is the record.