CVE-2026-76227: Renovate Information Disclosure Flaw

CVE-2026-76227 Overview

CVE-2026-76227 affects Renovate, an automated dependency update tool. The vulnerability exists in Renovate versions from 42.68.1 before 42.96.3, and from 42.68.1 before 43.4.4. Affected Docker images include renovate/renovate, mend/renovate-ce, renovate-ee-server, and renovate-ee-worker versions >=13.3.0 <13.6.0. Renovate fails to restrict environment variables to an allowlist when spawning child processes. Child processes such as npm install, postUpgradeTasks, and postUpdateOptions inherit full access to the Renovate process environment. This allows insiders or outside attackers with the ability to influence executed tasks to exfiltrate secrets accessible to the Renovate deployment. The issue is tracked under [CWE-526] (Cleartext Storage of Sensitive Information in an Environment Variable).

Critical Impact
Child processes spawned by Renovate inherit all parent environment variables, exposing tokens, credentials, and other secrets held by the Renovate deployment to attacker-controlled dependency scripts and post-upgrade tasks.

Affected Products

Renovate 42.68.1 to before 42.96.3
Renovate 42.68.1 to before 43.4.4
Docker images: renovate/renovate, mend/renovate-ce, renovate-ee-server, renovate-ee-worker>=13.3.0 <13.6.0

Discovery Timeline

2026-08-19 - CVE-2026-76227 published to NVD
2026-08-19 - Last updated in NVD database

Technical Details for CVE-2026-76227

Vulnerability Analysis

Renovate spawns child processes to perform package manager operations and user-configured tasks. Examples include running npm install, executing postUpgradeTasks, and applying postUpdateOptions. Affected versions do not filter the environment passed to these child processes against an allowlist. As a result, every variable in the Renovate process environment propagates to the spawned command.

Renovate deployments typically hold high-value secrets. These include Git host tokens, registry credentials, cloud provider keys, and CI system tokens. When a child process runs code influenced by a repository dependency or a repository configuration, that code can read the full environment and exfiltrate its contents.

Root Cause

The root cause is missing environment variable filtering at the child-process boundary. Node.js child_process APIs inherit the parent environment by default when no env option is set. Renovate did not enforce an allowlist scoped to the variables each task legitimately requires. This design maps to [CWE-526], where sensitive information stored in environment variables is exposed to code that should not receive it.

Attack Vector

The attack requires local execution within the context Renovate manages. A malicious dependency postinstall script executed during npm install can read the inherited environment. A repository owner can also configure postUpgradeTasks or leverage postUpdateOptions to run commands that dump environment variables. Any read secrets can be exfiltrated to attacker-controlled infrastructure over the network reachable to the Renovate worker.

See the GitHub Security Advisory and the VulnCheck Advisory for the maintainer's technical description.

Detection Methods for CVE-2026-76227

Indicators of Compromise

Unexpected outbound network connections from Renovate worker containers to non-registry hosts during dependency installation.
Child processes of Renovate such as node, npm, yarn, or shell interpreters reading /proc/self/environ or invoking env, printenv, or set.
Repository pull requests introducing new postUpgradeTasks entries or dependencies with suspicious postinstall scripts.

Detection Strategies

Inventory Renovate installations and compare running versions against 42.96.3 and 43.4.4.
Audit repository configurations for use of postUpgradeTasks and allowedPostUpgradeCommands allowlists on the Renovate host.
Review Renovate logs for commands invoking environment enumeration utilities during update runs.

Monitoring Recommendations

Alert on egress from Renovate worker nodes to destinations outside approved package registries and Git hosts.
Monitor process telemetry for printenv, env, and reads of /proc/*/environ originating under the Renovate process tree.
Track secret usage patterns and rotate any token that showed anomalous access during affected Renovate versions.

How to Mitigate CVE-2026-76227

Immediate Actions Required

Upgrade Renovate to 42.96.3 or 43.4.4 or later, and update Docker images to renovate-ee-worker and related components at 13.6.0 or later.
Rotate all secrets exposed to the Renovate process, including Git tokens, registry credentials, and cloud provider keys.
Restrict who can modify repository configuration for postUpgradeTasks and dependency manifests processed by Renovate.

Patch Information

The Renovate maintainers released fixed versions 42.96.3 and 43.4.4, along with corresponding Docker image updates at renovate-ee-worker13.6.0. The fix restricts child-process environments to an allowlist. Full details are available in the GitHub Security Advisory GHSA-8wc6-vgrq-x6cf.

Workarounds

Run Renovate with only the minimum secrets required, injecting per-run credentials rather than long-lived platform tokens.
Disable postUpgradeTasks and constrain allowedPostUpgradeCommands to a narrow, reviewed allowlist.
Isolate Renovate workers in dedicated containers or VMs with egress restricted to required Git hosts and package registries only.

bash

# Configuration example: verify Renovate version and constrain post-upgrade tasks
renovate --version

# In config.js, keep the allowedPostUpgradeCommands list tight
# and prefer disabling postUpgradeTasks unless strictly required
module.exports = {
  allowedPostUpgradeCommands: [],
  postUpgradeTasks: {
    commands: [],
    fileFilters: [],
    executionMode: 'update'
  }
};