# CVE-2026-67427: Flyto2 Core environment variable interpolation policy bypass

Source: https://junglewise.ai/threats/cve-2026-67427-flyto2-core-environment-variable-interpolation-policy-bypass  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-29. Updated: 2026-07-30  
License: CC BY 4.0 with a link back

CVE-2026-67427 · Severity: high · CVSS 8.6 · Published 2026-07-29

Flyto2 Core, a workflow engine, contains a security bypass that allows unauthorized access to sensitive server information. While the system is designed to block direct access to environment variables like API keys and database credentials, an attacker can use a specific text format to trick the engine into revealing these secrets. This could lead to the theft of cloud access keys or other critical credentials, potentially allowing further attacks on the organization's infrastructure.

Technologies: [flyto-core (PyPI)](https://junglewise.ai/threats/technologies/flyto-core). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2026-67427 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-67427 being exploited in the wild.

**How severe is CVE-2026-67427?** High severity, with a CVSS score of 8.6, published 29 July 2026.

**Which products and versions are affected?** flyto-core (PyPI) < 2.26.7, ECOSYSTEM:introduced=0,fixed=2.26.7.

**Is there a fix for CVE-2026-67427?** Yes. flyto-core (PyPI): upgrade to 2.26.7 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-67427 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-67427?** Check whether you run flyto-core (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- flyto-core (PyPI): upgrade to 2.26.7 or later

  ```sh
  pip install "flyto-core>=2.26.7"
  ```


## Technical details

A vulnerability in Flyto2 Core's workflow engine allows for the exfiltration of host environment variables. While the `env.get` and `env.load_dotenv` modules are denylisted by default to prevent secret exfiltration, the `VariableResolver` in `src/core/engine/variable_resolver.py` performs `${env.VAR}` interpolation without checking the module policy or an allowlist. An attacker can trigger this via the workflow API or MCP agent surface by providing parameters containing the interpolation syntax. The resolved secrets can then be exfiltrated through any allowed outbound module. This issue is patched in version 2.26.7.

## Affected products

- flytohub flyto-core < 2.26.7

## Identifiers

- CVE-2026-67427
- GHSA-hr7p-wg7r-hg9m
- PYSEC-2026-3570

## Timeline

- 2026-07-07: disclosed: Initial report by kaimandalic
- 2026-07-29: advisory: NVD publication date
- 2026-07-30: patched: GitHub Advisory published and version 2.26.7 released

## References

- [https://api.github.com/users/kaimandalic](https://api.github.com/users/kaimandalic)
- [https://github.com/kaimandalic](https://github.com/kaimandalic)
- [https://api.github.com/users/kaimandalic/gists%7B/gist_id%7D](https://api.github.com/users/kaimandalic/gists%7B/gist_id%7D)
- [https://api.github.com/users/kaimandalic/repos](https://api.github.com/users/kaimandalic/repos)
- [https://avatars.githubusercontent.com/u/204785446?v=4](https://avatars.githubusercontent.com/u/204785446?v=4)
- [https://api.github.com/users/kaimandalic/events%7B/privacy%7D](https://api.github.com/users/kaimandalic/events%7B/privacy%7D)

## Related threats

- [flytohub flyto-core SSRF bypass via IPv6 transition addresses](https://junglewise.ai/threats/cve-2026-55787-flytohub-flyto-core-ssrf-bypass-via-ipv6-transition-addresses)
- [flytohub flyto-core unauthenticated command execution in HTTP MCP](https://junglewise.ai/threats/cve-2026-55786-flytohub-flyto-core-unauthenticated-command-execution-in-http-mcp)
- [Flytohub Flyto2 Core path traversal in file-writing modules](https://junglewise.ai/threats/cve-2026-67429-flytohub-flyto2-core-path-traversal-in-file-writing-modules)
- [Flyto2 Core SSRF in multiple HTTP-emitting modules](https://junglewise.ai/threats/cve-2026-67428-flyto2-core-ssrf-in-multiple-http-emitting-modules)
- [Flyto2 Core SSRF and secret exfiltration in verification service](https://junglewise.ai/threats/cve-2026-67426-flyto2-core-ssrf-and-secret-exfiltration-in-verification-service)