# CVE-2020-8553: Kubernetes ingress-nginx Compromise of auth via subset/superset namespace names

> Attackers with namespace creation rights can overwrite basic auth files in other namespaces, leading to privilege escalation and unauthorized access.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 29 Jul 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-hhpm-74pm-hf35

## What is CVE-2020-8553?

CVE-2020-8553 is a medium-severity missing authorization vulnerability in Kubernetes ingress-nginx, published on 29 Jul 2020. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

The Kubernetes ingress-nginx component prior to version 0.28.0 allows a user with the ability to create namespaces and to read and create ingress objects to overwrite the password file of another ingress which uses nginx.ingress.kubernetes.io/auth-type: basic and which has a hyphenated namespace or secret name.

Weakness: CWE-610 (Externally Controlled Reference to a Resource in Another Sphere), CWE-73 (External Control of File Name or Path)

## Which versions are affected by CVE-2020-8553?

2 open source packages ship an affected version, including k8s.io/ingress-nginx. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `k8s.io/ingress-nginx` | Go | All versions | 0.28.0 |
| `k8s.io/ingress-nginx` | Go | All versions | 0.28.0 |

Products: Kubernetes Ingress-Nginx.

## How do I fix CVE-2020-8553?

Upgrade k8s.io/ingress-nginx to 0.28.0 or later.

## Is CVE-2020-8553 being exploited?

There is no known exploitation of CVE-2020-8553 in the wild and no public exploit code.

## Other vulnerabilities in Kubernetes ingress-nginx

- [CVE-2026-3288](https://insights.sbomify.com/CVE-2026-3288/): ingress-nginx rewrite-target nginx configuration injection (high 8.8)
- [CVE-2022-4886](https://insights.sbomify.com/CVE-2022-4886/): Ingress-nginx `path` sanitization can be bypassed with `log_format` directive (high 8.8)
- [CVE-2023-5043](https://insights.sbomify.com/CVE-2023-5043/): Ingress nginx annotation injection causes arbitrary command execution (high 7.6)
- [CVE-2023-5044](https://insights.sbomify.com/CVE-2023-5044/): Code injection via nginx.ingress.kubernetes.io/permanent-redirect annotation (high 7.6)
- [CVE-2021-25748](https://insights.sbomify.com/CVE-2021-25748/): Ingress-nginx `path` sanitization can be bypassed with newline character (high 7.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-8553 and fix it if it is affected.

What it is: CVE-2020-8553 is a medium-severity missing authorization vulnerability in Kubernetes ingress-nginx, published on 29 Jul 2020. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2020-8553 in the wild and no public exploit code.

Affected packages and fixed versions:
- k8s.io/ingress-nginx (Go): affected all versions; fixed in 0.28.0
- k8s.io/ingress-nginx (Go): affected all versions; fixed in 0.28.0

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-2020-8553/ (Markdown: https://insights.sbomify.com/CVE-2020-8553/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-8553
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-8553
- OSV: https://osv.dev/vulnerability/CVE-2020-8553

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-8553/
Summaries are generated and may contain mistakes; the official description above is the record.