Jupyter Server has a CORS Origin Validation Bypass via `re.match()` in `allow_origin_pat`
HighCVE-2026-40110 · Published May 5, 2026 · updated Sep 10, 2026
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 `
CVE-2026-40110: Jupyter high vulnerability | Advisories
Jupyter Server has a CORS Origin Validation Bypass via `re.match()` in `allow_origin_pat`
HighCVE-2026-40110 · Published May 5, 2026 · updated Sep 10, 2026
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 `
CVE-2026-40110: Jupyter high vulnerability | Advisories
Wednesdays: the week’s critical and high advisories in the AI and data stack, with the fixed versions. Only in weeks that have some.
\n\n### References\n\nhttps://github.com/jupyter-server/jupyter_server/pull/603\nhttps://docs.python.org/3/library/re.html#re.fullmatch\nhttps://docs.python.org/3/library/re.html#re.match","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:L/SC:L/SI:L/SA:L","cvssVersion":"4.0","severitySource":"github","cwes":["CWE-625","CWE-777"],"refs":["https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-24qx-w28j-9m6p","https://nvd.nist.gov/vuln/detail/CVE-2026-40110","https://github.com/jupyter-server/jupyter_server/pull/603","https://github.com/jupyter-server/jupyter_server/commit/057869a327c46730afede3eab0ca2d2e3e74acea","https://github.com/jupyter-server/jupyter_server/commit/49b34392feaa97735b3b777e3baf8f22f2a14ed8","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://github.com/jupyter-server/jupyter_server","https://github.com/pypa/advisory-database/tree/main/vulns/jupyter-server/PYSEC-2026-2187.yaml","https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40110.json"],"affected":[{"product":"jupyter","ecosystem":"PyPI","package":"jupyter-server","introduced":"","fixed":"2.18.0","lastAffected":""}],"changes":[]},"related":[{"id":"GHSA-mqcg-5x36-vfcg","cve":"CVE-2026-42557","aliases":["BIT-jupyter-base-notebook-2026-42557","BIT-jupyter-notebook-2026-42557","BIT-jupyterlab-2026-42557","CVE-2026-42557","PYSEC-2026-2537","PYSEC-2026-2681"],"summary":"JupyterLab's command linker attributes in HTML enable one-click command execution from untrusted content","title":"JupyterLab's command linker attributes in HTML enable one-click command execution from untrusted content","severity":"high","score":9.6,"product":"jupyter","productLabel":"","products":["jupyter"],"fixed":"4.5.7, 7.5.6","fixFirst":"4.5.7","fixedN":2,"published":"2026-05-06","modified":"2026-09-10","withdrawn":"","url":"https://github.com/advisories/GHSA-mqcg-5x36-vfcg","foundAt":"2026-09-24 23:00:26"},{"id":"GHSA-37w4-hwhx-4rc4","cve":"CVE-2026-42266","aliases":["BIT-jupyterlab-2026-42266","CVE-2026-42266","PYSEC-2026-164"],"summary":"JupyterLab has an Extension Manager API/GUI Policy Discrepancy, allowing 3rd party (malicious) extensions install via POST request","title":"Jupyter: improper input validation","severity":"high","score":8.8,"product":"jupyter","productLabel":"","products":["jupyter"],"fixed":"4.5.7","fixFirst":"4.5.7","fixedN":1,"published":"2026-05-05","modified":"2026-09-10","withdrawn":"","url":"https://github.com/advisories/GHSA-37w4-hwhx-4rc4","foundAt":"2026-09-24 23:00:26"},{"id":"GHSA-m68r-v472-jgq9","cve":"CVE-2026-40864","aliases":["BIT-jupyterhub-2026-40864","CVE-2026-40864","PYSEC-2026-2189"],"summary":"JupyterHub has cross-origin form POSTs bypass XSRF (CWE-352)","title":"JupyterHub has cross-origin form POSTs bypass XSRF (CWE-352)","severity":"medium","score":5.4,"product":"jupyter","productLabel":"","products":["jupyter"],"fixed":"5.4.5","fixFirst":"5.4.5","fixedN":1,"published":"2026-05-05","modified":"2026-09-10","withdrawn":"","url":"https://github.com/advisories/GHSA-m68r-v472-jgq9","foundAt":"2026-09-24 23:00:26"},{"id":"GHSA-5mrq-x3x5-8v8f","cve":"CVE-2026-40934","aliases":["CVE-2026-40934","PYSEC-2026-69"],"summary":"Jupyter Server's Authentication Cookies Remain Valid After Password Reset and Server Restart","title":"Jupyter Server's Authentication Cookies Remain Valid After Password Reset and Server Restart","severity":"high","score":6.8,"product":"jupyter","productLabel":"","products":["jupyter"],"fixed":"2.18.0","fixFirst":"2.18.0","fixedN":1,"published":"2026-05-05","modified":"2026-09-10","withdrawn":"","url":"https://github.com/advisories/GHSA-5mrq-x3x5-8v8f","foundAt":"2026-09-24 23:00:26"},{"id":"GHSA-5789-5fc7-67v3","cve":"CVE-2026-35397","aliases":["CVE-2026-35397","PYSEC-2026-68"],"summary":"Jupyter Server: Path Traversal via incorrect startswith() root directory check allows access to sibling directories","title":"Jupyter: path traversal","severity":"high","score":7.1,"product":"jupyter","productLabel":"","products":["jupyter"],"fixed":"2.18.0","fixFirst":"2.18.0","fixedN":1,"published":"2026-05-05","modified":"2026-09-10","withdrawn":"","url":"https://github.com/advisories/GHSA-5789-5fc7-67v3","foundAt":"2026-09-24 23:00:26"},{"id":"GHSA-qh7q-6qm3-653w","cve":"CVE-2025-61669","aliases":["CVE-2025-61669","PYSEC-2026-67"],"summary":"Jupyter Server has an open redirection vulnerability in `next` query parameter","title":"Jupyter Server has an open redirection vulnerability in `next` query parameter","severity":"medium","score":null,"product":"jupyter","productLabel":"","products":["jupyter"],"fixed":"2.18.0","fixFirst":"2.18.0","fixedN":1,"published":"2026-05-05","modified":"2026-09-10","withdrawn":"","url":"https://github.com/advisories/GHSA-qh7q-6qm3-653w","foundAt":"2026-09-24 23:00:26"}]}}
High9.6May 6