The ability to manage Kubernetes applications through Charts is an essential part of Helm's functionality. However, recently, a vulnerability (CVE-2025-32386) was discovered that potentially causes memory exhaustion and compromises the overall stability of the application. This blog post discusses the details of this vulnerability, provides a code snippet and links to the original references, and demonstrates how upgrading to Helm v3.17.3 can safeguard your application against this exploit.

Exploit Details

The vulnerability lies within the way Helm handles chart archive files. A malicious actor can craft a chart archive file in such a way that, when uncompressed, it becomes significantly larger than its compressed size (for example, with an >800x difference in size). When Helm processes this specially crafted chart, it can exhaust the system memory, causing the application to crash or terminate unexpectedly.

Code Snippet

The following code snippet demonstrates how the vulnerability might be exploited in a maliciously crafted chart archive file:

# Snippet showing maliciously crafted chart (potential_memory_leak_chart.tgz)
apiVersion: v1
kind: ConfigMap
metadata:
  name: {{ .Release.Name }}-config
data:
  # 800x larger when uncompressed
  file.txt: |
    {{ (randAlphaNum 25600000) | b64enc }}

Original References

Please follow these links for a deeper understanding of the vulnerability and its potential impact.
- Helm Security Issue: CVE-2025-32386
- Helm Release Notes

Solution: Upgrading to Helm v3.17.3
This security vulnerability has been successfully resolved in the Helm v3.17.3 release. By updating to the latest version, you ensure that your application is protected from memory exhaustion issues caused by the loading of crafted chart archive files. Here's a step-by-step guide on upgrading your Helm installation:

1. Download the latest release Helm v3.17.3 from the official GitHub repository.
2. Follow the official installation guide to install or upgrade your Helm installation.

Conclusion

Keeping your Helm installation up-to-date is crucial for protecting your application from potential security threats. By upgrading to Helm v3.17.3, you safeguard your application from the memory exhaustion vulnerability described in CVE-2025-32386. Make sure to follow best practices by always using the latest version of Helm and staying informed about newly discovered vulnerabilities and potential exploits. If you have any questions or concerns about the content covered in this blog post, feel free to reach out to us in the comments below.

Timeline

Published on: 04/09/2025 23:15:37 UTC
Last modified on: 04/11/2025 15:40:10 UTC