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GHSA-96qw-h329-v5rg

HighCVSS 7.5 / 10
Published Jan 8, 2026·Last modified Feb 3, 2026
Affected Components(0)

No affected components available

Description

Summary

Since 2017, the default webpack plugins have passed the entire process.env to EnvironmentPlugin. This pattern exposed ALL build environment variables to client-side JavaScript bundles whenever application code (or any dependency) referenced process.env.VARIABLE_NAME.

This is not a regression - the vulnerable code has existed since the original Webpacker implementation. No recent code change in Shakapacker triggered this issue.

Impact

Any environment variable in the build environment that is referenced in client-side code (including third-party dependencies) is embedded directly into the JavaScript bundle. This includes:

  • DATABASE_URL - Database credentials
  • AWS_SECRET_ACCESS_KEY - AWS credentials
  • RAILS_MASTER_KEY - Rails encrypted credentials key
  • STRIPE_SECRET_KEY, TWILIO_AUTH_TOKEN - Third-party API keys
  • Any other secrets present in the build environment

Severity: Critical - secrets are exposed in publicly accessible JavaScript files.

Root Cause

The original code used:

new webpack.EnvironmentPlugin(process.env)

This makes every environment variable available for substitution. If any code references process.env.SECRET_KEY, that value is embedded in the bundle.

Patches

Upgrade to version 9.5.0 or later, which uses an allowlist approach that only exposes NODE_ENV, RAILS_ENV, and WEBPACK_SERVE by default.

Workarounds

If developers cannot upgrade immediately:

  1. Audit client-side code and dependencies for any process.env.X references to sensitive variables
  2. Remove sensitive variables from the build environment
  3. Override the default plugins with a custom webpack/rspack config using an explicit allowlist

Migration

After upgrading, if client-side code needs access to specific environment variables:

Option 1: Use the SHAKAPACKER_PUBLIC_ prefix (recommended)

# Variables with this prefix are automatically exposed
export SHAKAPACKER_PUBLIC_API_URL="https://api.example.com"

Option 2: Use SHAKAPACKER_ENV_VARS

SHAKAPACKER_ENV_VARS=API_URL,FEATURE_FLAG bundle exec rails assets:precompile

Action Required

After upgrading, rotate any secrets that may have been exposed in previously compiled JavaScript bundles.

Resources

  • Fix PR: https://github.com/shakacode/shakapacker/pull/857
Risk Scores
Base Score
7.5

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information.

Threat Intelligence
6.9

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
N/A

Probability that this vulnerability will be exploited in the wild within the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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High severity
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