Description
JupyterHub through 6.0.1 contains an identifier collision vulnerability that allows authenticated users to overwrite another user's named-server OAuth client by registering a hyphenated username. Attackers holding a name like alice-prod can overwrite the client for alice's server prod, breaking OAuth login and revoking tokens by stopping their own server.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| jupyterhub | jupyterhub | ≤ 6.0.1 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | jupyterhub | No fix yet | — |
| Debian 13 | jupyterhub | No fix yet | — |
| Debian 12 | jupyterhub | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | jupyterhub | No fix yet | — |
| Ubuntu 26.04 LTS | jupyterhub | No fix yet | — |
| Ubuntu 24.04 LTS | jupyterhub | No fix yet | — |
| Ubuntu 22.04 LTS | jupyterhub | No fix yet | — |
References
- https://hackmd.io/@haind/jupyterhub-oauth-client-id-cross-user-collision third-party-advisory
- https://github.com/jupyterhub/jupyterhub/blob/3e516c6f382b481e815ec455befb2f14d80d337b/jupyterhub/user.py#L563-L567 technical-description
- https://github.com/jupyterhub/jupyterhub/blob/3e516c6f382b481e815ec455befb2f14d80d337b/jupyterhub/oauth/provider.py#L719-L754 technical-description
- https://github.com/jupyterhub/jupyterhub/blob/3e516c6f382b481e815ec455befb2f14d80d337b/jupyterhub/user.py#L1174-L1186 technical-description
- https://github.com/jupyterhub/jupyterhub product
- VulnCheck Advisory: JupyterHub through 6.0.1 OAuth Client ID Collision via Unescaped Hyphen third-party-advisory