PYSEC-2026-1479

Impact

jupyter_scheduler is missing an authentication check in Jupyter Server on an API endpoint (GET /scheduler/runtime_environments) which lists the names of the Conda environments on the server. In affected versions, jupyter_scheduler allows an unauthenticated user to obtain the list of Conda environment names on the server. This reveals any information that may be present in a Conda environment name.

This issue does not allow an unauthenticated third party to read, modify, or enter the Conda environments present on the server where jupyter_scheduler is running. This issue only reveals the list of Conda environment names.

Impacted versions: >=1.0.0,<=1.1.5 ; ==1.2.0 ; >=1.3.0,<=1.8.1 ; >=2.0.0,<=2.5.1

Patches

• jupyter-scheduler==1.1.6
• jupyter-scheduler==1.2.1
• jupyter-scheduler==1.8.2
• jupyter-scheduler==2.5.2

Workarounds

Server operators who are unable to upgrade can disable the jupyter-scheduler extension with:

jupyter server extension disable jupyter-scheduler

References

If you have any questions or comments about this advisory we ask that you contact AWS/Amazon Security via our vulnerability reporting page [1] or directly via email to aws-security@amazon.com. Please do not create a public GitHub issue.

[1] Vulnerability reporting page: https://aws.amazon.com/security/vulnerability-reporting