# CVE-2021-36157: Path traversal in Grafana Cortex

> Attackers can read sensitive files via directory traversal in the X-Scope-OrgID header, exposing deployment contents in error messages.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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:** 3 Aug 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-jphm-g89m-v42p

## What is CVE-2021-36157?

CVE-2021-36157 is a medium-severity path traversal vulnerability in n/a, published on 3 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in Grafana Cortex through 1.9.0. The header value X-Scope-OrgID is used to construct file paths for rules files, and if crafted to conduct directory traversal such as ae ../../sensitive/path/in/deployment pathname, then Cortex will attempt to parse a rules file at that location and include some of the contents in the error message. (Other Cortex API requests can also be sent a malicious OrgID header, e.g., tricking the ingester into writing metrics to a different location, but the effect is nuisance rather than information disclosure.)

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2021-36157?

2 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 to 1.9.0 | None |
| `github.com/cortexproject/cortex` | Go | All versions to 1.9.0 | None |

Products: Linuxfoundation Cortex.

## How do I fix CVE-2021-36157?

No fix has been published for CVE-2021-36157 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-36157 being exploited?

There is no known exploitation of CVE-2021-36157 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-2021-31232](https://insights.sbomify.com/CVE-2021-31232/): Improper input validation in CNCF Cortex (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-36157 and fix it if it is affected.

What it is: CVE-2021-36157 is a medium-severity path traversal vulnerability in n/a, published on 3 Aug 2021. 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-2021-36157 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/cortexproject/cortex (Go): affected all versions up to 1.9.0; no fix listed
- github.com/cortexproject/cortex (Go): affected all versions up to 1.9.0; no fix listed

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-2021-36157/ (Markdown: https://insights.sbomify.com/CVE-2021-36157/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-36157
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-36157
- OSV: https://osv.dev/vulnerability/CVE-2021-36157

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-36157/
Summaries are generated and may contain mistakes; the official description above is the record.