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.
- 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
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
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 | 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 include Nektos Act.
How do I fix CVE-2026-34041?
Upgrade github.com/nektos/act to 0.2.86 or later.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-34041 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34041 exists.
Sources
Also known as GHSA-xmgr-9pqc-h5vw, GO-2026-4891.