# CVE-2026-34041: act: Unrestricted set-env and add-path command processing enables environment injection

> Attackers can inject environment variables or modify PATH via workflow commands, potentially leading to code execution or privilege escalation in local GitHub Actions runners.

- **Severity:** High 7.7 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 31 Mar 2026
- **Updated:** 2 Apr 2026
- **Also known as:** GHSA-xmgr-9pqc-h5vw, GO-2026-4891

## What is CVE-2026-34041?

CVE-2026-34041 is a high-severity code injection vulnerability in nektos act, published on 31 Mar 2026. An attacker can exploit it over the internet without logging in, 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. Prior to version 0.2.86, act unconditionally processes the deprecated ::set-env:: and ::add-path:: workflow commands, which was disabled due to environment injection risks. When a workflow step echoes untrusted data to stdout, an attacker can inject these commands to set arbitrary environment variables or modify the PATH for all subsequent steps in the job. This issue has been patched in version 0.2.86.

Weakness: CWE-74 (Improper Neutralization of Special Elements in Output Used by a Downstream Component)

## Which versions are affected by CVE-2026-34041?

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 | 0.2.86 |
| `github.com/nektos/act` | Go | All versions | 0.2.86 |
| `github.com/nektos/act` | Go | All versions | 0.2.86 |

Products: Nektos Act.

## How do I fix CVE-2026-34041?

Upgrade github.com/nektos/act to 0.2.86 or later.

## Is CVE-2026-34041 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34041 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34041 and fix it if it is affected.

What it is: CVE-2026-34041 is a high-severity code injection vulnerability in nektos act, published on 31 Mar 2026. An attacker can exploit it over the internet without logging in, 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-2026-34041 exists.

Affected packages and fixed versions:
- github.com/nektos/act (Go): affected all versions; fixed in 0.2.86
- github.com/nektos/act (Go): affected all versions; fixed in 0.2.86
- github.com/nektos/act (Go): affected all versions; fixed in 0.2.86

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-2026-34041/ (Markdown: https://insights.sbomify.com/CVE-2026-34041/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34041
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34041
- OSV: https://osv.dev/vulnerability/CVE-2026-34041

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34041/
Summaries are generated and may contain mistakes; the official description above is the record.