medium5.3
CVE-2026-54338
JupyterHub has Unauthenticated Denial of Service via Unbounded Username Logging on Failed Login
Impact
JupyterHub is software that allows users to create a multi-user server for Jupyter notebooks. Prior to 5.5.0, invalid input to form-based login authenticators can place an unbounded attacker-controlled username in failed-login logs, allowing an unauthenticated attacker to consume logging and storage resources. This issue is fixed in version 5.5.0.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | jupyterhub | < 5.5.0 | 5.5.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-p43p-whwx-q52h
- https://github.com/jupyterhub/jupyterhub/security/advisories/GHSA-p43p-whwx-q52h
- https://nvd.nist.gov/vuln/detail/CVE-2026-54338
- https://github.com/jupyterhub/jupyterhub/commit/d6dc595f84b7509969686da31d87d6d69e7fce0a