Codecov security update: Open Zaak is not affected

On April 15th, we were informed by Codecov that they had a security incident that possibly affected Open Zaak repositories. We have checked our repositories and verified that everything is as expected.

Unless you are using the latest image tag of Open Zaak or Open Notificaties Docker Hub images, no action is required. If you do use the latest tag in any of those images, and those images are old enough to no longer have build logs, then our advice is to pull these images again. There is no indication that they have been compromised, but we cannot guarantee this because of the nature of how Docker Hub operates.

Below, you can find a detailed breakdown of the security incident at Codecov, how it possibly impacted Open Zaak projects and how we verified that we were not impacted by this.

Codecov and their security incident

Codecov is a tool used in Open Zaak, Open Notificaties and the CMIS adapter used to track and visualize code coverage statistics. During the process of automatically testing these codebases, statistics are collected on which lines of code are hit, partially hit or missed during the test runs. Divided by the number of total lines in the code base, you arrive at a coverage percentage.

The collection of statistics is performed as part of our automated Continuous Integration pipeline on Github. The raw statistics are uploaded to Codecov's infrastructure using their Github Action, which in turn uses the "global bash uploader" hosted on Codecov's website.

It is this bash script that was altered by an unauthorized third party, and actively used to exfiltrate access tokens from Github Action workflows to third party servers. For more details, please read the detailed statement from Codecov.

This exfiltration was possible from the beginning of January 2021, until April 2021.

Impact on the Open Zaak projects

Codecov is used in four projects:

  • Open Zaak
  • Open Notificaties
  • CMIS adapter
  • vng-selectielijst

The Open Zaak, Open Notificaties and VNG-Selectielijst projects automatically publish Docker Images to Docker Hub after a succesful build on either the main branch or tagged releases. CMIS Adapter is automatically published to the Python Packaging index on tagged releases.

To be able to do this, credentials are provided to the Github Workflow context in the form of organization and/or repository secrets. The modified Codecov bash uploader was able to extract these credentials outside of the workflow scope.

The impact per project is summarized below.

Open Zaak

Open Zaak uses the Github Action, and is therefore affected. However, we know that during a CI run, the code is checked out from the repository and remained trusted code. From this code, a Docker image is produced which has a sha256 checksum. The checksum reported in Github Workflows log is the trusted, uncompromised checksum.

If an attacker would overwrite the image tag using the extracted token, this would happen after the build finishes, and the image would have a different checksum.

We verified the checksums for Open Zaak releases between Jan. 1st and April 1st:

  • 1.3.4

    CI produced the fe10bb4f402119d4b4073388bd60cacca4cea3964ad2c95c4f3507bdb6c377ad checksum, and on Docker Hub we find the same checksum.

  • 1.3.5

    CI produced the f83a8e33eb6572e196721914a999fff3eca1ef9b742499fbdebe91780491d87c checksum, and on Docker Hub we find the same checksum.

For people using the latest image tag, you can verify this manually. The master (past) and main (present) branches map to the latest image tag. CI run logs can be seen on Github. Note that CI logs older than three months are no longer available, which is why we recommend to re-pull the latest tag to be sure.

Open Notificaties

The situation for Open Notificaties is similar to Open Zaak above.

The relevant releases are:

  • 1.1.3

    CI produced the 47d001e89b904a1d4450b0d165c072289ba34ee95c7ff41e28b8440c9689a83b checksum, and on Docker Hub we find the same checksum.

  • 1.1.4

    CI produced the 2532abe52a37fd8ff90dcdb3564a187be520a973fef94574740e8f340258644f checksum, and on Docker Hub we find the same checksum.

Users of the latest tag should follow the advice as for Open Zaak.

CMIS adapter

While we use Codecov, we do not use the Github Action, but the global Python uploader from PyPI. This uploader was not affected.


While we use Codecov, we do not use the Github Action, but the global Python uploader from PyPI. This uploader was not affected.

Which steps have we taken?

On April 15th, shortly after learning about the incident, we have revoked any access tokens/credentials exposed to Github Workflows:

  • Docker access token for the maykinmediaci account
  • PyPI access token for the maykinmedia account

At the same time, we verified the Docker Image checksums of the Open Zaak releases.

On April 16th, we verified the Open Notificaties checksums, and checked which other projects could potentially be impacted. We also drafted this news article.

On May 7th and the following days, the news article was published and announced on various communication channels.


If you have any questions at this, do not hesitate to contact us on the Common Ground Slack in the #open-zaak channel. Members of the Technical Steering Group are usually around.

If you need to report any security incidents, please follow our documented guidelines.