CVE-2024-26147 Overview
CVE-2024-26147 is an uninitialized variable vulnerability affecting Helm, the popular package manager for Kubernetes Charts. The vulnerability exists in how Helm parses index.yaml and plugin.yaml files when these files are missing expected metadata content. When Helm encounters index or plugin YAML files lacking all metadata, the application triggers a panic, resulting in a denial of service condition.
This vulnerability impacts both the Helm client and the Helm SDK. In the SDK, the issue manifests when using the LoadIndexFile or DownloadIndexFile functions in the repo package, or the LoadDir function in the plugin package. For Helm client users, the vulnerability affects repository addition operations and can completely disable all Helm functionality if a malicious plugin is present, as Helm inspects all known plugins on each invocation.
Critical Impact
A malicious actor could craft a repository with an empty or malformed index.yaml file, or distribute a malicious plugin with an incomplete plugin.yaml, causing Helm to panic and crash. This could effectively render Helm unusable in affected environments.
Affected Products
- Helm versions prior to 3.14.2
- Helm SDK versions prior to 3.14.2
- Applications using affected LoadIndexFile, DownloadIndexFile, or LoadDir functions
Discovery Timeline
- 2024-02-21 - CVE-2024-26147 published to NVD
- 2025-01-09 - Last updated in NVD database
Technical Details for CVE-2024-26147
Vulnerability Analysis
The vulnerability is classified under CWE-457 (Use of Uninitialized Variable) and CWE-908 (Use of Uninitialized Resource). When Helm parses YAML configuration files for repositories or plugins, it expects certain metadata fields to be present. The code fails to properly validate or initialize variables before use when these expected fields are absent from the YAML structure.
The network-accessible nature of this vulnerability is particularly concerning because repository index files are typically fetched from remote sources. An attacker controlling or compromising a Helm chart repository could serve a malformed index.yaml file that triggers the panic condition when users attempt to add or update the repository.
Root Cause
The root cause is improper handling of YAML files that lack expected metadata content. When parsing these files, Helm attempts to access properties of data structures that were never properly initialized due to the missing metadata. This leads to a nil pointer dereference or similar runtime error, causing the Go application to panic.
The specific code paths affected are:
- LoadIndexFile function in the repo package
- DownloadIndexFile function in the repo package
- LoadDir function in the plugin package
Attack Vector
The vulnerability can be exploited through two primary attack vectors:
Malicious Repository: An attacker could set up or compromise a Helm chart repository and serve an index.yaml file with missing metadata. When a victim adds this repository using helm repo add or updates their repositories, Helm panics.
Malicious Plugin: An attacker could distribute a malicious plugin containing a plugin.yaml file with missing metadata. Once installed, this plugin causes Helm to panic on every subsequent invocation, as Helm inspects all plugins at startup.
The vulnerability is exploitable over the network without authentication, as adding public Helm repositories is a common operation that does not require privileges.
Detection Methods for CVE-2024-26147
Indicators of Compromise
- Unexpected Helm client crashes with panic messages related to nil pointer or uninitialized variable access
- Presence of unfamiliar plugins in the Helm plugins directory (helm plugin list)
- Recently added repositories with suspicious or malformed index.yaml files
- Helm commands consistently failing with runtime panics after adding a new repository or plugin
Detection Strategies
- Monitor Helm client execution for abnormal termination patterns and panic stack traces
- Implement file integrity monitoring on Helm plugin directories to detect unauthorized plugin additions
- Validate downloaded index.yaml files against expected schema before processing
- Enable detailed logging for Helm operations to capture repository and plugin interaction events
Monitoring Recommendations
- Configure alerting for repeated Helm process crashes in CI/CD pipelines and deployment automation
- Implement network monitoring to detect connections to unknown or suspicious Helm repositories
- Audit the list of configured Helm repositories and installed plugins periodically
- Monitor for changes to Helm configuration files and plugin directories
How to Mitigate CVE-2024-26147
Immediate Actions Required
- Upgrade Helm to version 3.14.2 or later immediately
- Audit currently installed Helm plugins for any unfamiliar or suspicious entries
- Review configured Helm repositories and remove any untrusted sources
- If Helm is completely non-functional due to a malicious plugin, manually remove suspicious plugins from the filesystem
Patch Information
Helm has released version 3.14.2 which resolves this vulnerability. The fix is tracked in GitHub commit bb4cc9125503a923afb7988f3eb478722a8580af. For complete details on the vulnerability and remediation, refer to the GitHub Security Advisory GHSA-r53h-jv2g-vpx6.
Organizations using the Helm SDK should update to version 3.14.2 or implement defensive coding practices to handle potential panics.
Workarounds
- For SDK users on versions prior to 3.14.2, wrap calls to LoadIndexFile, DownloadIndexFile, and LoadDir in recover blocks to catch panics gracefully
- Manually remove malicious plugins from the Helm plugins directory if the client is non-functional (typically located at ~/.local/share/helm/plugins on Linux or %APPDATA%\helm\plugins on Windows)
- Implement repository allowlisting to prevent users from adding untrusted Helm repositories
- Validate YAML file contents before passing to Helm SDK functions in custom tooling
# Remove a malicious plugin manually (Linux/macOS)
rm -rf ~/.local/share/helm/plugins/<malicious-plugin-name>
# Remove a malicious plugin manually (Windows)
rmdir /s /q %APPDATA%\helm\plugins\<malicious-plugin-name>
# Verify Helm version after upgrade
helm version --short
# Expected output: v3.14.2 or later
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
