# CVE-2021-31232: Improper input validation in CNCF Cortex

> Attackers can read arbitrary local files via webhook or templates when the experimental API is enabled in Cortex Alertmanager.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/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:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Apr 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-m45g-f45x-vv22, GO-2022-0915

## What is CVE-2021-31232?

CVE-2021-31232 is a medium-severity path traversal vulnerability in n/a, published on 30 Apr 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The Alertmanager in CNCF Cortex before 1.8.1 has a local file disclosure vulnerability when -experimental.alertmanager.enable-api is used. The HTTP basic auth password_file can be used as an attack vector to send any file content via a webhook. The alertmanager templates can be used as an attack vector to send any file content because the alertmanager can load any text file specified in the templates list.

## Which versions are affected by CVE-2021-31232?

3 open source packages ship an affected version, including github.com/cortexproject/cortex. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/cortexproject/cortex` | Go | All versions | 1.8.1 |
| `github.com/cortexproject/cortex` | Go | All versions | 1.8.1 |
| `github.com/cortexproject/cortex` | Go | All versions | 1.8.1 |

Products: Linuxfoundation Cortex.

## How do I fix CVE-2021-31232?

Upgrade github.com/cortexproject/cortex to 1.8.1 or later.

## Is CVE-2021-31232 being exploited?

There is no known exploitation of CVE-2021-31232 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2022-23536](https://insights.sbomify.com/CVE-2022-23536/): Alertmanager can expose local files content via specially crafted config (medium 6.5)
- [CVE-2021-36157](https://insights.sbomify.com/CVE-2021-36157/): Path traversal in Grafana Cortex (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-31232 and fix it if it is affected.

What it is: CVE-2021-31232 is a medium-severity path traversal vulnerability in n/a, published on 30 Apr 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-31232 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/cortexproject/cortex (Go): affected all versions; fixed in 1.8.1
- github.com/cortexproject/cortex (Go): affected all versions; fixed in 1.8.1
- github.com/cortexproject/cortex (Go): affected all versions; fixed in 1.8.1

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-2021-31232/ (Markdown: https://insights.sbomify.com/CVE-2021-31232/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-31232
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-31232
- OSV: https://osv.dev/vulnerability/CVE-2021-31232

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-31232/
Summaries are generated and may contain mistakes; the official description above is the record.