# CVE-2018-12021: Singularity Incorrect Access Control

> A malicious user can access sensitive information in Singularity containers using the overlay option on systems supporting overlay file systems.

- **Severity:** Medium 6.5 (`CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 5 Jul 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-4x32-h296-rg6j, UBUNTU-CVE-2018-12021, openSUSE-SU-2018:1969-1

## What is CVE-2018-12021?

CVE-2018-12021 is a medium-severity vulnerability in n/a, published on 5 Jul 2018. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Singularity 2.3.0 through 2.5.1 is affected by an incorrect access control on systems supporting overlay file system. When using the overlay option, a malicious user may access sensitive information by exploiting a few specific Singularity features.

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

## Which versions are affected by CVE-2018-12021?

2 open source packages ship an affected version, including github.com/hpcng/singularity. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/hpcng/singularity` | Go | From 2.3.0 | 2.5.2 |
| `github.com/hpcng/singularity` | Go | From 2.3.0 | 2.5.2 |
| `singularity` | SUSE:Package Hub 12 SP3 | All versions | 2.3.2-11.1 |

Products: Sylabs Singularity.

## How do I fix CVE-2018-12021?

Upgrade github.com/hpcng/singularity to 2.5.2 or later.

## Is CVE-2018-12021 being exploited?

There is no known exploitation of CVE-2018-12021 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2021-33027](https://insights.sbomify.com/CVE-2021-33027/): Weak cryptography in n/a (critical 9.8)
- [CVE-2021-33622](https://insights.sbomify.com/CVE-2021-33622/): Other in n/a (critical 9.8)
- [CVE-2018-19295](https://insights.sbomify.com/CVE-2018-19295/): Sylabs Singularity Improper Input Validation (high 7.8)
- [CVE-2020-13845](https://insights.sbomify.com/CVE-2020-13845/): Execution Control List (ECL) Is Insecure in Singularity (high 7.5)
- [CVE-2020-13846](https://insights.sbomify.com/CVE-2020-13846/): "Verify All" Returns Success Despite Validation Failures in Singularity (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-12021 and fix it if it is affected.

What it is: CVE-2018-12021 is a medium-severity vulnerability in n/a, published on 5 Jul 2018. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2018-12021 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/hpcng/singularity (Go): affected from 2.3.0; fixed in 2.5.2
- github.com/hpcng/singularity (Go): affected from 2.3.0; fixed in 2.5.2

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-2018-12021/ (Markdown: https://insights.sbomify.com/CVE-2018-12021/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-12021
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-12021
- OSV: https://osv.dev/vulnerability/CVE-2018-12021

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-12021/
Summaries are generated and may contain mistakes; the official description above is the record.