CVE-2020-26261

Name: CVE-2020-26261
Creator: NVD / NIST
Published: 2020-12-09T17:15:30.603+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.9/10EPSS 0.47%

Last modified Jun 17, 2026

CVE-2020-26261 is a high-severity vulnerability rated 7.9/10 on the CVSS scale. jupyterhub-systemdspawner enables JupyterHub to spawn single-user notebook servers using systemd. In jupyterhub-systemdspawner before version 0.15 user API tokens issued to single-user servers are specified in the environment of systemd units. EPSS estimates a 0.47% chance of exploitation in the next 30 days.

Description

jupyterhub-systemdspawner enables JupyterHub to spawn single-user notebook servers using systemd. In jupyterhub-systemdspawner before version 0.15 user API tokens issued to single-user servers are specified in the environment of systemd units. These tokens are incorrectly accessible to all users. In particular, the-littlest-jupyterhub is affected, which uses systemdspawner by default. This is patched in jupyterhub-systemdspawner v0.15

Metrics

CVSS 3.1

7.9/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

EPSS Probability

0.47%

37.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Jupyterhub	Systemdspawner	< 0.15

References

https://github.com/jupyterhub/systemdspawner/blob/master/CHANGELOG.md#v015Release Notes, Third Party Advisory
https://github.com/jupyterhub/systemdspawner/commit/a4d08fd2ade1cfd0ef2c29dc221e649345f23580Patch, Third Party Advisory
https://github.com/jupyterhub/systemdspawner/security/advisories/GHSA-cg54-gpgr-4rm6Third Party Advisory
https://pypi.org/project/jupyterhub-systemdspawner/Product, Third Party Advisory
https://github.com/jupyterhub/systemdspawner/blob/master/CHANGELOG.md#v015Release Notes, Third Party Advisory
https://github.com/jupyterhub/systemdspawner/commit/a4d08fd2ade1cfd0ef2c29dc221e649345f23580Patch, Third Party Advisory
https://github.com/jupyterhub/systemdspawner/security/advisories/GHSA-cg54-gpgr-4rm6Third Party Advisory
https://pypi.org/project/jupyterhub-systemdspawner/Product, Third Party Advisory

Timeline

Published: Dec 9, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-26261?

How severe is CVE-2020-26261?

CVE-2020-26261 has a CVSS score of 7.9/10 (HIGH severity). The EPSS model estimates a 0.47% probability of exploitation in the next 30 days.

How do I fix CVE-2020-26261?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-26261?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST