Description

In JetBrains Junie GitHub Action before 1.8.0 code execution with workflow credentials was possible via fork updates

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.4",
  "pubDate": "2026-11-06T17:17:24.283Z",
  "pubdate": "2026-11-06T17:17:24.283Z",
  "executiveSummary": "A critical vulnerability exists in the JetBrains Junie GitHub Action prior to version 1.8.0, allowing for unauthorized code execution.\nThe vulnerability originates from improper handling of workflow credentials when processing updates from forked repositories.\nAn unauthenticated attacker can leverage this flaw to gain unauthorized access to workflow secrets and execution environments.\nThe impact includes full compromise of the CI/CD pipeline, potential leakage of sensitive environment variables, and the ability to execute arbitrary commands within the context of the GitHub Action runner.\nExploitation is feasible through malicious fork-based pull requests, which trigger the vulnerable code path during the workflow execution process.\nOrganizations relying on affected versions of Junie are exposed to significant supply chain security risks until the component is updated.",
  "technicalDetails": "The vulnerability resides in how the JetBrains Junie GitHub Action manages and evaluates trust boundaries during workflow execution, specifically concerning event triggers originating from repository forks.\nIn versions prior to 1.8.0, the action does not sufficiently restrict the usage of repository-scoped credentials or workflow tokens when processing updates derived from forked branches. This flaw allows a malicious actor to inject code that is subsequently executed by the runner using the permissions granted to the original workflow.\nThe attack flow begins when an attacker submits a pull request from a forked repository to the upstream target. The Junie action, failing to sanitize or appropriately restrict the environment context for fork-sourced events, allows the execution of user-controllable input as part of the CI process.\nBecause the action operates with access to the repository's workflow credentials, the injected code inherits the privilege level associated with the GitHub Action token. This grants the attacker the ability to interact with the GitHub API, exfiltrate repository secrets, or modify the repository state, depending on the scope of the token provided to the action.\nThe root cause is an improper validation logic within the action's execution flow that fails to distinguish between trusted source code and potentially adversarial content introduced via external forks. The component effectively elevates the trust level of unverified pull request payloads to match the legitimate workflow, bypassing intended security boundaries.\nThe vulnerability is platform-specific to the GitHub Actions ecosystem and requires the target repository to be configured such that the Junie action is triggered by external contributions. Successful exploitation results in post-exploitation capabilities ranging from data exfiltration—such as reading protected environment variables and secrets—to secondary supply chain attacks by poisoning build artifacts or modifying deployment configurations."
}