# CVE-2026-8467: phenixdigital phoenix_storybook code injection in playground rendering

Source: https://junglewise.ai/threats/cve-2026-8467-phenixdigital-phoenix-storybook-code-injection-in-playground  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-05-20. Updated: 2026-06-09  
License: CC BY 4.0 with a link back

CVE-2026-8467 · Severity: critical · CVSS 9.5 · Published 2026-05-20

PhoenixStorybook is a tool used by developers to showcase and test UI components in Elixir-based web applications. A critical security flaw in its "playground" feature allows any user on the internet to execute arbitrary commands on the server without needing a password. This could lead to a complete takeover of the server, theft of sensitive data, or disruption of services.

Technologies: [Phenix Digital Storybook](https://junglewise.ai/threats/technologies/storybook). Vendors: [Phenix Digital](https://junglewise.ai/threats/vendors/phenix-digital).

## Quick answers

**Is CVE-2026-8467 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-8467 being exploited in the wild.

**How severe is CVE-2026-8467?** Critical severity, with a CVSS score of 9.5, published 20 May 2026.

**Which products and versions are affected?** Phenix Digital Storybook 0.5.0 to 1.0.x (fixed in 1.1.0).

**Is there a fix for CVE-2026-8467?** A patch was published on 2026-06-09: Version 1.1.0 released Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-8467 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-8467?** Check whether you run Phenix Digital Storybook 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.

## Technical details

A remote code execution (RCE) vulnerability exists in phoenix_storybook versions 0.5.0 through 1.0.x. The flaw is located in the `psb-assign` event handler within `PhoenixStorybook.Story.PlaygroundPreviewLive`, which accepts unsanitized attribute values from WebSocket clients. These values are interpolated directly into a HEEx template string in `ComponentRenderer.attributes_markup/1` without escaping. Because the resulting template is compiled and evaluated using `Code.eval_quoted_with_env/3` with full Elixir `Kernel` access and no sandboxing, an attacker can inject arbitrary Elixir expressions (e.g., `System.cmd/2`) to execute operating system commands. The vulnerability is patched in version 1.1.0.

## Affected products

- phenixdigital phoenix_storybook >= 0.5.0, < 1.1.0

## Identifiers

- CVE-2026-8467
- GHSA-55hg-8qxv-qj4p

## Timeline

- 2026-05-20: disclosed
- 2026-06-09: advisory: GitHub Advisory published
- 2026-06-09: patched: Version 1.1.0 released

## References

- [https://api.github.com/users/maennchen](https://api.github.com/users/maennchen)
- [https://github.com/maennchen](https://github.com/maennchen)
- [https://api.github.com/users/maennchen/gists%7B/gist_id%7D](https://api.github.com/users/maennchen/gists%7B/gist_id%7D)
- [https://api.github.com/users/maennchen/repos](https://api.github.com/users/maennchen/repos)
- [https://avatars.githubusercontent.com/u/333918?v=4](https://avatars.githubusercontent.com/u/333918?v=4)
- [https://api.github.com/users/maennchen/events%7B/privacy%7D](https://api.github.com/users/maennchen/events%7B/privacy%7D)