user-readable api tokens in systemd units for JupyterHub

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

7.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:U · score source

EPSS

• CVE-2020-26261: 0.48% estimated exploitation activity in the next 30 days; percentile 41.50 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact user API tokens issued to single-user servers are specified in the environment of systemd units, which are accessible to all users. In particular, the-littlest-jupyterhub is affected, which uses systemdspawner by default. Patches Patched in jupyterhub-systemdspawner v0.15 Workarounds No workaround other than upgrading systemdspawner to 0.15 For more information If you have any questions or comments about this advisory: Open a thread in the Jupyter forum Email us at security@ipython.org

Published by the source

9 Dec 2020, 16:27 UTC

Last modified by the source

10 Sep 2026, 03:49 UTC

Source last checked

26 Oct 2026, 13:20 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-cg54-gpgr-4rm6

2. Revision 2 · amended · 24 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-cg54-gpgr-4rm6

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# Patch Next advisory brief: CVE-2020-26261

Advisory: user-readable api tokens in systemd units for JupyterHub
IDs: CVE-2020-26261, GHSA-cg54-gpgr-4rm6
Record: https://patchnext.com/advisories/cve-2020-26261 (revision 3, source checked 26 Oct 2026, 13:20 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: jupyterhub-systemdspawner 0.15.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI jupyterhub-systemdspawner: affected < 0.15.0; fixed in 0.15.0

## Suggested inspection (read-only)
- `python -m pip show jupyterhub-systemdspawner`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on jupyterhub-systemdspawner.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-cg54-gpgr-4rm6 (OSV record GHSA-cg54-gpgr-4rm6 lists affected ranges: PyPI jupyterhub-systemdspawner >=0 <0.15.0 (fixed))
- Verified: https://github.com/advisories/GHSA-cg54-gpgr-4rm6 (GitHub-reviewed advisory GHSA-cg54-gpgr-4rm6 lists affected ranges: PyPI jupyterhub-systemdspawner >=0 <0.15.0)

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