# CVE-2021-41087: Improperly Implemented path matching for in-toto-golang

> Authenticated attackers can bypass DISALLOW rules in in-toto-golang layouts using path traversal semantics in attestations, compromising supply chain integrity.

- **Severity:** Medium 5.6 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:H/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:** 21 Sep 2021
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-vrxp-mg9f-hwf3, GO-2022-0936

## What is CVE-2021-41087?

CVE-2021-41087 is a medium-severity path traversal vulnerability in in-toto-golang, published on 21 Sep 2021. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

in-toto-golang is a go implementation of the in-toto framework to protect software supply chain integrity. In affected versions authenticated attackers posing as functionaries (i.e., within a trusted set of users for a layout) are able to create attestations that may bypass DISALLOW rules in the same layout. An attacker with access to trusted private keys, may issue an attestation that contains a disallowed artifact by including path traversal semantics (e.g., foo vs dir/../foo). Exploiting this vulnerability is dependent on the specific policy applied. The problem has been fixed in version 0.3.0.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), CWE-345 (Insufficient Verification of Data Authenticity)

## Which versions are affected by CVE-2021-41087?

3 open source packages ship an affected version, including github.com/in-toto/in-toto-golang. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/in-toto/in-toto-golang` | Go | All versions | 0.3.0 |
| `github.com/in-toto/in-toto-golang` | Go | All versions | 0.3.0 |
| `github.com/in-toto/in-toto-golang` | Go | All versions | 0.3.0 |

Products: In-Toto In-Toto-Golang.

## How do I fix CVE-2021-41087?

Upgrade github.com/in-toto/in-toto-golang to 0.3.0 or later.

## Is CVE-2021-41087 being exploited?

There is no known exploitation of CVE-2021-41087 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-41087 and fix it if it is affected.

What it is: CVE-2021-41087 is a medium-severity path traversal vulnerability in in-toto-golang, published on 21 Sep 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-2021-41087 in the wild and no public exploit code.

Affected packages and fixed versions:
- github.com/in-toto/in-toto-golang (Go): affected all versions; fixed in 0.3.0
- github.com/in-toto/in-toto-golang (Go): affected all versions; fixed in 0.3.0
- github.com/in-toto/in-toto-golang (Go): affected all versions; fixed in 0.3.0

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-2021-41087/ (Markdown: https://insights.sbomify.com/CVE-2021-41087/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-41087
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-41087
- OSV: https://osv.dev/vulnerability/CVE-2021-41087

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-41087/
Summaries are generated and may contain mistakes; the official description above is the record.