Cloud Composer Flaw Exposes GCP to PyPI Package Infiltration

By Dan Evert, CCNP   Published: 04/23/25   Updated: 10/21/26   3 min read

Cloud Composer Flaw Exposes GCP to PyPI Package Infiltration

In brief:

Software flaws are nothing new. Cloud services and their tangle of dependencies keep producing odd security gaps, though, and researchers recently found one in Google Cloud Platform (GCP), inside Google’s Cloud Composer service.

Background on the Flaw

Tenable researchers found the flaw in Cloud Composer, Google’s managed orchestration service built on Apache Airflow for running and automating workflows. An identity with permission to update a Composer environment could tell it to install a malicious Python package from PyPI (the Python Package Index). Simple trick. Big payoff.

The Technical Details

The package’s installation scripts ran inside Cloud Build using Cloud Build’s default service account, which normally holds broad permissions across the project, so an attacker with fairly limited Composer rights could steal that account’s token and escalate to much wider control. From there, data theft or deeper movement into the cloud environment was possible.

Google’s Swift Response

Google fixed the issue by having Composer install PyPI packages with the environment’s own service account instead of the Cloud Build default. New Composer 2 environments from version 2.10.2 and all Composer 3 environments got the fix, and existing Composer 2 environments needed updating.

Google credited the researchers through its coordinated disclosure process, and the case shows how much cloud providers depend on outside researchers to find gaps like this.

Implications for Cloud Security

The lesson is about third-party integrations and service accounts in cloud services. Organizations depend more on the cloud every year. Each service and integration is a possible attack path, and each needs close scrutiny.

Cloud environments are complex, and every component should be treated as a possible risk. Misconfigurations and over-broad default permissions are often simple. Exploited, they can do serious damage, which is why regular, thorough audits of service-account permissions matter.

Future Considerations

Cloud services keep spreading across industries, so defenders need to adapt and act early. Google and Tenable caught and fixed this one, and it is still a reminder to stay alert.

Cloud providers, security researchers and customers need to keep talking and working together to strengthen defenses. New technology brings deeper dependencies. Those make security harder, and the work has to be shared.

Check your Composer permissions

The Cloud Composer flaw is a prompt for every company to review and tighten its cloud security. Threats keep changing. Learning from each incident and putting strong preventive measures in place could make the difference next time.

How will the industry respond, and what new fixes will emerge to close gaps like this? The answer will likely shape cloud security for years.

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Dan Evert, CCNP

Dan Evert is a self proclaimed Router Jockey. Dan got heavily involved in networking right out of high school and has never looked back! Dan is giving back by working with high school students to get them involved and interested in Networking and Security.