CVE-2020-26275

medium
Published 2020-12-21 · Modified 2026-05-19
CVSS v3
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CVSS v2
VIR risk
5.5

Description

The Jupyter Server provides the backend (i.e. the core services, APIs, and REST endpoints) for Jupyter web applications like Jupyter notebook, JupyterLab, and Voila. In Jupyter Server before version 1.1.1, an open redirect vulnerability could cause the jupyter server to redirect the browser to a different malicious website. All jupyter servers running without a base_url prefix are technically affected, however, these maliciously crafted links can only be reasonably made for known jupyter server hosts. A link to your jupyter server may *appear* safe, but ultimately redirect to a spoofed server on the public internet. This same vulnerability was patched in upstream notebook v5.7.8. This is fixed in jupyter_server 1.1.1. If upgrade is not available, a workaround can be to run your server on a url prefix: "jupyter server --ServerApp.base_url=/jupyter/".

Predictions

Exploit likelihood
30%
Patch ETA

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2020-26275

OS impact

OSVersionStatusFixed in
debian debianbookwormfixed1.1.1-1
debian debianbullseyefixed1.1.1-1
debian debianforkyfixed1.1.1-1
debian debiansidfixed1.1.1-1
debian debiantrixiefixed1.1.1-1

Package impact

EcosystemPackageVulnerableFixed
python PyPIjupyter-server<1.1.11.1.1
python PyPIjupyter-server
python PyPIjupyter-server<85e4abccf6ea9321d29153f73b0bd72ccb3a6bca||<1.1.185e4abccf6ea9321d29153f73b0bd72ccb3a6bca
PIPjupyter-server< 1.1.11.1.1

References

Verify integrity in audit chain (admin only). AS-IS.