{"id":"UBUNTU-CVE-2026-40110","details":"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.","modified":"2026-06-30T18:17:37.547885313Z","published":"2026-05-05T22:16:00Z","upstream":["CVE-2026-40110"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-40110"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-40110"},{"type":"REPORT","url":"https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-24qx-w28j-9m6p"},{"type":"REPORT","url":"https://github.com/jupyter-server/jupyter_server/pull/603"},{"type":"REPORT","url":"https://github.com/jupyter-server/jupyter_server/commit/057869a327c46730afede3eab0ca2d2e3e74acea"},{"type":"REPORT","url":"https://github.com/jupyter-server/jupyter_server/commit/49b34392feaa97735b3b777e3baf8f22f2a14ed8"}],"affected":[{"package":{"name":"jupyter-server","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/jupyter-server?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.2-1","1.13.1-1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.13.1-1","binary_name":"jupyter-server"},{"binary_name":"python3-jupyter-server","binary_version":"1.13.1-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40110.json"}},{"package":{"name":"jupyter-server","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/jupyter-server?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.23.3-1","1.23.3-2"],"ecosystem_specific":{"binaries":[{"binary_version":"1.23.3-2","binary_name":"jupyter-server"},{"binary_name":"python3-jupyter-server","binary_version":"1.23.3-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40110.json"}},{"package":{"name":"jupyter-server","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/jupyter-server?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.14.2-5","2.15.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"jupyter-server","binary_version":"2.15.0-1"},{"binary_name":"python3-jupyter-server","binary_version":"2.15.0-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40110.json"}},{"package":{"name":"jupyter-server","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/jupyter-server?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.15.0-1","2.17.0-1"],"ecosystem_specific":{"binaries":[{"binary_version":"2.17.0-1","binary_name":"jupyter-server"},{"binary_name":"python3-jupyter-server","binary_version":"2.17.0-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40110.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"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"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N"},{"type":"Ubuntu","score":"medium"}]}