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GHSA-384w-5v3f-q499 oauthenticator

MEDIUMFix: jupyterhub/oauthenticator@a4aac19

GHSA-384w-5v3f-q499 is a medium-severity (CVSS 6.3) CWE-863 vulnerability in oauthenticator. A fix is available for oauthenticator — see the affected versions and patch details below.

Base class whitelist configuration ignored in OAuthenticator

Also known asCVE-2020-26250PYSEC-2020-68
Published
Dec 1, 2020
Updated
Jul 8, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 19, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.1%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs65th percentile — riskier than 65% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

GHSA-384w-5v3f-q499 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 377,166 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

1 pkg affected
🐍oauthenticator

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Impact

What goes wrong?

The deprecated (in jupyterhub 1.2) configuration Authenticator.whitelist, which should be transparently mapped to Authenticator.allowed_users with a warning, is instead ignored by OAuthenticator classes, resulting in the same behavior as if this configuration has not been set. If this is the only mechanism of authorization restriction (i.e. no group or team restrictions in configuration) then all authenticated users will be allowed. Provider-based restrictions, including deprecated values such as GitHubOAuthenticator.org_whitelist are not affected.

Who is impacted?

All users of OAuthenticator 0.12.0 and 0.12.1 with JupyterHub 1.2 (JupyterHub Helm chart 0.10.0-0.10.5) who use the admin.whitelist.users configuration in the jupyterhub helm chart or the c.Authenticator.whitelist configuration directly. Users of other deprecated configuration, e.g. c.GitHubOAuthenticator.team_whitelist are not affected.

If you see a log line like this and expect a specific list of allowed usernames:

[I 2020-11-27 16:51:54.528 JupyterHub app:1717] Not using allowed_users. Any authenticated user will be allowed.

you are likely affected.

Patches

  • Replacing deprecated c.Authenticator.whitelist = ... with c.Authenticator.allowed_users = ... avoids the issue.
  • Update oauthenticator to 0.12.2
  • Update jupyterhub helm chart to 0.10.6

If any users have been authorized during this time who should not have been, they must be deleted via the API or admin interface, per the documentation.

Workarounds

Replacing c.Authenticator.whitelist = ... with c.Authenticator.allowed_users = ... avoids the issue.

In the jupyterhub helm chart prior to 0.10.6, this can be done via hub.extraConfig:

auth:
  allowedUsers:
  - user1
  - user2

hub:
  extraConfig:
    allowedUsers: |
        # set new field not exposed in helm chart < 0.10.6
        set_config_if_not_none(c.Authenticator, "allowed_users", "auth.allowedUsers")

For more information

If you have any questions or comments about this advisory:

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIoauthenticator0.12.0&&< 0.12.20.12.2pip install --upgrade 'oauthenticator==0.12.2'

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for oauthenticator, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update oauthenticator to 0.12.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-384w-5v3f-q499 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-384w-5v3f-q499 can be triaged on real exposure rather than presence alone.

Tailored to GHSA-384w-5v3f-q499. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Impact __What goes wrong?__ The deprecated (in jupyterhub 1.2) configuration `Authenticator.whitelist`, which should be transparently mapped to `Authenticator.allowed_users` with a warning, is instead ignored by OAuthenticator classes, resulting in the same behavior as if this configuration has not been set. If this is the only mechanism of authorization restriction (i.e. no group or team restrictions in configuration) then all authenticated users will be allowed. Provider-based restrictions, including deprecated values such as `GitHubOAuthenticator.org_whitelist` are **not** affected.
O3 Security · Impact-Aware SCA

Is GHSA-384w-5v3f-q499 in your dependencies?

O3 Security finds GHSA-384w-5v3f-q499 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-384w-5v3f-q499: oauthenticator | O3 Security