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Not in CISA KEV

Jupyter Server has a CORS Origin Validation Bypass via `re.match()` in `allow_origin_pat`GHSA-24qx-w28j-9m6p

Fix: jupyter-server/jupyter_server#603

GHSA-24qx-w28j-9m6p is a CWE-777 vulnerability in jupyter-server. A fix is available for jupyter-server — see the affected versions and patch details below.

Also known asCVE-2026-40110PYSEC-2026-2187
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • A successful exploit gives an attacker total control of the affected component, not partial access.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-24qx-w28j-9m6p.

EPSS Exploitation Probability

via FIRST.org ↗
0.3%probability of exploitation in next 30 days
Lower Risk-0.03%
Lower risk than most CVEs24th percentile — riskier than 24% of all scored CVEsHighest risk
0.00%0.28%0.56%0.84%0.3%0.3%Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected
🐍jupyter-server

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

Jupyter Server is the backend for Jupyter web applications. In versions 2.17.0 and earlier, the Origin header validation uses Python's 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.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIjupyter-serverall versions2.18.0pip install --upgrade 'jupyter-server==2.18.0'

Affected Products

1 product · 1 configurations
Application
jupyter serverjupyter
< 2.18.0
range

Detection & mitigation playbook

Open-source dependency
  1. Detect

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

  2. Fix

    Update jupyter-server to 2.18.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-24qx-w28j-9m6p 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.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatImportant
Workaround published by Red Hat
Administrators should review and update the `allow_origin_pat` configuration in Jupyter Server to use a more precise regular expression. Ensure the pattern explicitly anchors to the end of the string (e.g., by adding `$` to the end of the regex) to prevent partial domain matches. After modifying the configuration, the Jupyter Server service must be restarted for the changes to take effect.
Source: Red Hat security advisory for GHSA-24qx-w28j-9m6p (CC BY 4.0)
ProductFixed inAdvisory
Red Hat Migration Toolkit for Applications 8.2mta/mta-solution-server-rhel9:1784109883RHSA-2026:43038
Red Hat OpenShift AI 3.3rhoai/odh-workbench-jupyter-datascience-cpu-py312-rhel9:1790331087RHSA-2026:73987

Frequently Asked Questions

Jupyter Server uses `re.match()` to validate the Origin header against the `allow_origin_pat` configuration. Since `re.match()` only anchors at the start of the string, an attacker who controls a domain like `http://trusted.example.com.evil.com/` passes validation against a pattern intended to match only `trusted.example.com`. ### Impact <=2.17.0 ### Patches 057869a327c46730afede3eab0ca2d2e3e74acea, 49b34392feaa97735b3b777e3baf8f22f2a14ed8 ### Workarounds Wrap your `allow_origin_pat` value with `^` and `$` ### References https://github.com/jupyter-server/jupyter_server/pull/603 https
O3 Security · Impact-Aware SCA

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