Description
Jupyter Server is the backend for Jupyter web applications. In jupyter_server versions through 2.17.0, the next query parameter in the login flow is insufficiently validated in `LoginFormHandler._redirect_safe()`, which allows redirects to arbitrary external domains via values such as `///example.com`. An attacker can use a crafted login URL to redirect users to a malicious site and facilitate phishing attacks. This issue is fixed in version 2.18.0.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| jupyter-server | jupyter_server | <= 2.17.0 | — |
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 | jupyter-server | 2.20.0-1 | — |
| Debian 13 | jupyter-server | No fix yet | — |
| Debian 12 | jupyter-server | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | jupyter-server | No fix yet | — |
| Ubuntu 26.04 LTS | jupyter-server | No fix yet | — |
| Ubuntu 25.10 | jupyter-server | No fix yet | — |
| Ubuntu 24.04 LTS | jupyter-server | No fix yet | — |
| Ubuntu 22.04 LTS | jupyter-server | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | python-jupyter-server | 2.18.1-1.1 | openSUSE-SU-2026:10710-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | jupyter-server | 2.18.2-r0 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | jupyter-server | < 2.18.0 | 2.18.0 | GHSA-qh7q-6qm3-653w |
Advisories 1
- openSUSE-SU-2026:10710-1 python311-jupyter-server-2.18.1-1.1 on GA media SUSE / openSUSE Security Updates · May 7, 2026