The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added a new high-severity GitHub supply chain vulnerability to its Known Exploited Vulnerabilities (KEV) catalog. This serious flaw impacts the popular tj-actions/changed-files GitHub Action, putting sensitive developer secrets at risk.
CVE-2025-30066: A High-Impact Vulnerability in GitHub Actions
Tracked as CVE-2025-30066 with a CVSS score of 8.6, the vulnerability stems from injected malicious code within the tj-actions/changed-files GitHub Action. It allows remote attackers to extract secrets directly from action logs.
According to CISA, the flaw can expose valuable credentials such as:
- AWS access keys
- GitHub personal access tokens (PATs)
- npm tokens
- Private RSA keys
With this data, attackers could gain unauthorized access to cloud environments and private repositories.
Cascading Supply Chain Attack Uncovered
Cybersecurity firm Wiz revealed the attack is part of a larger cascading supply chain compromise. Threat actors first targeted the reviewdog/action-setup@v1 GitHub Action, which is a dependency used by tj-actions/eslint-changed-files.
Because tj-actions/changed-files runs this action with a Personal Access Token (PAT), the attackers gained a foothold that enabled deeper infiltration. The compromise likely occurred around March 11, 2025, while the breach of tj-actions/changed-files was detected shortly before March 14.
How Attackers Exploited the GitHub CI/CD Pipeline
Once inside, the attackers injected a Base64-encoded malicious payload into a file named install.sh within the CI/CD workflow. When executed, this payload exposed sensitive secrets by printing them into the GitHub Actions logs.
While only the v1 tag of reviewdog/action-setup was affected, it was enough to carry out this sophisticated supply chain attack. The exploit highlights the risk of using loosely pinned versions in automated workflows.
Investigations revealed that attackers gained control of a compromised GitHub Personal Access Token, which allowed them to modify the tj-actions/changed-files repository and insert the malicious code.
Growing Risks in GitHub Organization Management
Experts also warned that the reviewdog GitHub organization might have unintentionally expanded its attack surface. By adding new contributors through automated invites, the organization increased the risk of compromised access or insider threats.
Such practices make open-source projects attractive targets for supply chain attacks, especially when contributor access is not tightly controlled.
Critical Recommendations: Update and Secure Your Workflows
CISA advises federal agencies and developers using the vulnerable action to update to tj-actions/changed-files version 46.0.1 by April 4, 2025. Delaying the update leaves projects exposed to ongoing attacks.
However, experts caution that updating alone may not eliminate the risk. Without addressing the root cause, such attacks could easily happen again.
Best Practices to Strengthen GitHub Action Security
Developers and teams should adopt the following security measures:
- Review and audit past workflows for any suspicious activity or unauthorized changes
- Immediately rotate any exposed secrets such as AWS keys, GitHub PATs, or npm tokens
- Pin all GitHub Actions to specific commit hashes instead of version tags to avoid silent updates
- Replace compromised or risky actions with safer alternatives
The Bigger Picture: A Wake-Up Call for CI/CD Security
This GitHub Action supply chain attack is a stark reminder of the growing threats within modern software development pipelines. As CI/CD workflows become more complex, securing every component is no longer optional.
The addition of this vulnerability to CISA’s KEV catalog underlines the need for greater vigilance. Supply chain threats are real, and open-source tools are increasingly being weaponized.
