Jupyter Server is the backend for Jupyter web applications. In versions 2.17.0 and earlier, the Origin header validation uses Pythons re.match() to check incoming origins against the allow_origin_pat configuration value. Because re.match() only anchors at the start of the string and does not require a full match, a pattern intended to match only a trusted domain (e.g., trusted.example.com) will also match any origin that begins with that domain followed by additional characters (e.g., trusted.example.com.evil.com). An attacker who controls such a domain can bypass the CORS origin restriction and make cross-origin requests to the Jupyter Server API from an untrusted site. This issue has been fixed in version 2.18.0.
Weakness
The product uses a regular expression to perform neutralization, but the regular expression is not anchored and may allow malicious or malformed data to slip through.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Jupyter_server | Jupyter | * | 2.18.0 (excluding) |
| Red Hat Migration Toolkit for Applications 8.2 | RedHat | mta/mta-solution-server-rhel9:1784109883 | * |
| Red Hat OpenShift AI 3.3 | RedHat | rhoai/odh-workbench-jupyter-datascience-cpu-py312-rhel9:1790331087 | * |
| Red Hat OpenShift AI 3.3 | RedHat | rhoai/odh-workbench-jupyter-minimal-cpu-py312-rhel9:1790260954 | * |
| Red Hat OpenShift AI 3.3 | RedHat | rhoai/odh-workbench-jupyter-minimal-cuda-py312-rhel9:1790072130 | * |
| Red Hat OpenShift AI 3.3 | RedHat | rhoai/odh-workbench-jupyter-minimal-rocm-py312-rhel9:1790072109 | * |
| Red Hat OpenShift AI 3.3 | RedHat | rhoai/odh-workbench-jupyter-pytorch-cuda-py312-rhel9:1789651387 | * |
| Red Hat OpenShift AI 3.3 | RedHat | rhoai/odh-workbench-jupyter-pytorch-llmcompressor-cuda-py312-rhel9:1789651389 | * |
| Red Hat OpenShift AI 3.3 | RedHat | rhoai/odh-workbench-jupyter-pytorch-rocm-py312-rhel9:1789651385 | * |
| Red Hat OpenShift AI 3.3 | RedHat | rhoai/odh-workbench-jupyter-tensorflow-cuda-py312-rhel9:1790077488 | * |
| Red Hat OpenShift AI 3.3 | RedHat | rhoai/odh-workbench-jupyter-tensorflow-rocm-py312-rhel9:1789983680 | * |
| Red Hat OpenShift AI 3.3 | RedHat | rhoai/odh-workbench-jupyter-trustyai-cpu-py312-rhel9:1790260954 | * |
| Jupyter-server | Ubuntu | questing | * |
Potential Mitigations
References
- https://github.com/jupyter-server/jupyter_server/commit/057869a327c46730afede3eab0ca2d2e3e74acea
- https://github.com/jupyter-server/jupyter_server/commit/49b34392feaa97735b3b777e3baf8f22f2a14ed8
- https://github.com/jupyter-server/jupyter_server/pull/603
- https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-24qx-w28j-9m6p
- https://access.redhat.com/errata/RHSA-2026:43038
- https://access.redhat.com/security/cve/CVE-2026-40110
- https://bugzilla.redhat.com/show_bug.cgi?id=2466912
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40110.json