# CVE-2023-22726: Unrestricted file upload leading to privilege escalation in act

> Attackers can exploit path traversal in the artifact server to overwrite arbitrary files, leading to privilege escalation on the host.

- **Severity:** High 8.0 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 20 Jan 2023
- **Updated:** 10 Mar 2025
- **Also known as:** GHSA-pc99-qmg4-rcff, GO-2023-1504

## What is CVE-2023-22726?

CVE-2023-22726 is a high-severity path traversal vulnerability in nektos act, published on 20 Jan 2023. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

### Official description

act is a project which allows for local running of github actions. The artifact server that stores artifacts from Github Action runs does not sanitize path inputs. This allows an attacker to download and overwrite arbitrary files on the host from a Github Action. This issue may lead to privilege escalation. The /upload endpoint is vulnerable to path traversal as filepath is user controlled, and ultimately flows into os.Mkdir and os.Open. The /artifact endpoint is vulnerable to path traversal as the path is variable is user controlled, and the specified file is ultimately returned by the server. This has been addressed in version 0.2.40. Users are advised to upgrade. Users unable to upgrade may, during implementation of Open and OpenAtEnd for FS, ensure to use ValidPath() to check against path traversal or clean the user-provided paths manually.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), CWE-434 (Unrestricted Upload of File with Dangerous Type)

## Which versions are affected by CVE-2023-22726?

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


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/nektos/act` | Go | All versions | 0.2.40 |
| `github.com/nektos/act` | Go | All versions | 0.2.40 |
| `github.com/nektos/act` | Go | All versions | 0.2.40 |

Products: Act Project Act.

## How do I fix CVE-2023-22726?

Upgrade github.com/nektos/act to 0.2.40 or later.

## Is CVE-2023-22726 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-22726 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-22726 and fix it if it is affected.

What it is: CVE-2023-22726 is a high-severity path traversal vulnerability in nektos act, published on 20 Jan 2023. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-22726 exists.

Affected packages and fixed versions:
- github.com/nektos/act (Go): affected all versions; fixed in 0.2.40
- github.com/nektos/act (Go): affected all versions; fixed in 0.2.40
- github.com/nektos/act (Go): affected all versions; fixed in 0.2.40

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-2023-22726/ (Markdown: https://insights.sbomify.com/CVE-2023-22726/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-22726
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-22726
- OSV: https://osv.dev/vulnerability/CVE-2023-22726

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-22726/
Summaries are generated and may contain mistakes; the official description above is the record.