GHSA-96QW-H329-V5RG
Vulnerability from github – Published: 2026-01-08 21:13 – Updated: 2026-01-08 21:13Summary
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 credentialsAWS_SECRET_ACCESS_KEY- AWS credentialsRAILS_MASTER_KEY- Rails encrypted credentials keySTRIPE_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
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "shakapacker"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "9.5.0"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "RubyGems",
"name": "shakapacker"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "9.5.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-200"
],
"github_reviewed": true,
"github_reviewed_at": "2026-01-08T21:13:37Z",
"nvd_published_at": null,
"severity": "HIGH"
},
"details": "### Summary\n\nSince 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`.\n\nThis is not a regression - the vulnerable code has existed since the original Webpacker implementation. No recent code change in Shakapacker triggered this issue.\n\n### Impact\n\nAny 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:\n\n- `DATABASE_URL` - Database credentials\n- `AWS_SECRET_ACCESS_KEY` - AWS credentials \n- `RAILS_MASTER_KEY` - Rails encrypted credentials key\n- `STRIPE_SECRET_KEY`, `TWILIO_AUTH_TOKEN` - Third-party API keys\n- Any other secrets present in the build environment\n\n**Severity**: Critical - secrets are exposed in publicly accessible JavaScript files.\n\n### Root Cause\n\nThe original code used:\n```javascript\nnew webpack.EnvironmentPlugin(process.env)\n```\n\nThis makes every environment variable available for substitution. If any code references `process.env.SECRET_KEY`, that value is embedded in the bundle.\n\n### Patches\n\nUpgrade to version 9.5.0 or later, which uses an allowlist approach that only exposes `NODE_ENV`, `RAILS_ENV`, and `WEBPACK_SERVE` by default.\n\n### Workarounds\n\nIf developers cannot upgrade immediately:\n1. Audit client-side code and dependencies for any `process.env.X` references to sensitive variables\n2. Remove sensitive variables from the build environment\n3. Override the default plugins with a custom webpack/rspack config using an explicit allowlist\n\n### Migration\n\nAfter upgrading, if client-side code needs access to specific environment variables:\n\n**Option 1: Use the `SHAKAPACKER_PUBLIC_` prefix (recommended)**\n```bash\n# Variables with this prefix are automatically exposed\nexport SHAKAPACKER_PUBLIC_API_URL=\"https://api.example.com\"\n```\n\n**Option 2: Use `SHAKAPACKER_ENV_VARS`**\n```bash\nSHAKAPACKER_ENV_VARS=API_URL,FEATURE_FLAG bundle exec rails assets:precompile\n```\n\n### Action Required\n\nAfter upgrading, **rotate any secrets** that may have been exposed in previously compiled JavaScript bundles.\n\n### Resources\n\n- Fix PR: https://github.com/shakacode/shakapacker/pull/857",
"id": "GHSA-96qw-h329-v5rg",
"modified": "2026-01-08T21:13:37Z",
"published": "2026-01-08T21:13:37Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/shakacode/shakapacker/security/advisories/GHSA-96qw-h329-v5rg"
},
{
"type": "WEB",
"url": "https://github.com/shakacode/shakapacker/pull/857"
},
{
"type": "WEB",
"url": "https://github.com/shakacode/shakapacker/commit/3e06781b18383c5c2857ed3a722f7b91bdc1bc0e"
},
{
"type": "PACKAGE",
"url": "https://github.com/shakacode/shakapacker"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
],
"summary": "Shakapacker has environment variable leak via EnvironmentPlugin that exposes secrets to client-side bundles"
}
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Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
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- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
How durations are calculated
Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.
Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.
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