LTI JupyterHub Authenticator does not properly validate JWT Signature

Exploitation

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

CVSS

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

EPSS

• CVE-2023-25574: 0.36% estimated exploitation activity in the next 30 days; percentile 29.30 (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 Only users that has configured a JupyterHub installation to use the authenticator class LTI13Authenticator are influenced. LTI13Authenticator that was introduced in jupyterhub-ltiauthenticator 1.3.0 wasn't validating JWT signatures. This is believed to allow the LTI13Authenticator to authorize a forged request granting access to existing and new user identities. Patches None. Workarounds None. References - This code segment didn't validate a JWT signature.

Published by the source

25 Feb 2025, 17:48 UTC

Last modified by the source

5 Jun 2026, 18:00 UTC

Source last checked

26 Oct 2026, 13:42 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-mcgx-2gcr-p3hp

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-mcgx-2gcr-p3hp

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# Patch Next advisory brief: CVE-2023-25574

Advisory: LTI JupyterHub Authenticator does not properly validate JWT Signature
IDs: CVE-2023-25574, GHSA-mcgx-2gcr-p3hp
Record: https://patchnext.com/advisories/cve-2023-25574 (revision 2, source checked 26 Oct 2026, 13:42 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 10.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: jupyterhub-ltiauthenticator 1.4.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI jupyterhub-ltiauthenticator: affected >= 1.3.0, <= 1.3.0; fixed in 1.4.0

## Suggested inspection (read-only)
- `python -m pip show jupyterhub-ltiauthenticator`: 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-ltiauthenticator.
- 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-mcgx-2gcr-p3hp (OSV record GHSA-mcgx-2gcr-p3hp lists affected ranges: PyPI jupyterhub-ltiauthenticator >=1.3.0 <1.4.0 (fixed))
- Verified: https://github.com/advisories/GHSA-mcgx-2gcr-p3hp (GitHub-reviewed advisory GHSA-mcgx-2gcr-p3hp lists affected ranges: PyPI jupyterhub-ltiauthenticator >=1.3.0 <=1.3.0)

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