{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-40110","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-04-09T01:41:38.536Z","datePublished":"2026-05-05T21:29:31.323Z","dateUpdated":"2026-06-30T12:08:58.866Z"},"containers":{"cna":{"title":"jupyter-server CORS origin validation bypass via unanchored regex in allow_origin_pat","problemTypes":[{"descriptions":[{"cweId":"CWE-777","lang":"en","description":"CWE-777: Regular Expression without Anchors","type":"CWE"}]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"PASSIVE","vulnConfidentialityImpact":"HIGH","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"LOW","subConfidentialityImpact":"LOW","subIntegrityImpact":"LOW","subAvailabilityImpact":"LOW","baseScore":7.6,"baseSeverity":"HIGH","vectorString":"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","version":"4.0"}}],"references":[{"name":"https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-24qx-w28j-9m6p","tags":["x_refsource_CONFIRM"],"url":"https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-24qx-w28j-9m6p"},{"name":"https://github.com/jupyter-server/jupyter_server/pull/603","tags":["x_refsource_MISC"],"url":"https://github.com/jupyter-server/jupyter_server/pull/603"},{"name":"https://github.com/jupyter-server/jupyter_server/commit/057869a327c46730afede3eab0ca2d2e3e74acea","tags":["x_refsource_MISC"],"url":"https://github.com/jupyter-server/jupyter_server/commit/057869a327c46730afede3eab0ca2d2e3e74acea"},{"name":"https://github.com/jupyter-server/jupyter_server/commit/49b34392feaa97735b3b777e3baf8f22f2a14ed8","tags":["x_refsource_MISC"],"url":"https://github.com/jupyter-server/jupyter_server/commit/49b34392feaa97735b3b777e3baf8f22f2a14ed8"}],"affected":[{"vendor":"jupyter-server","product":"jupyter_server","versions":[{"version":"<= 2.17.0","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-05-05T21:29:31.323Z"},"descriptions":[{"lang":"en","value":"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."}],"source":{"advisory":"GHSA-24qx-w28j-9m6p","discovery":"UNKNOWN"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-07T03:55:47.112003Z","id":"CVE-2026-40110","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-05-07T12:47:52.707Z"}},{"affected":[{"cpes":["cpe:/a:redhat:migration_toolkit_applications:8"],"defaultStatus":"affected","product":"Migration Toolkit for Applications 8","vendor":"Red Hat"},{"cpes":["cpe:/a:redhat:openshift_ai"],"defaultStatus":"affected","product":"Red Hat OpenShift AI (RHOAI)","vendor":"Red Hat"}],"datePublic":"2026-05-05T21:29:31.323Z","descriptions":[{"lang":"en","value":"A flaw was found in Jupyter Server. The Origin header validation, which uses Python's `re.match()` function, does not correctly validate incoming origins against allowed patterns. This allows a remote attacker to bypass Cross-Origin Resource Sharing (CORS) restrictions by crafting a malicious domain that partially matches a trusted one. Consequently, the attacker can make unauthorized cross-origin requests to the Jupyter Server API from an untrusted site, potentially leading to sensitive information disclosure or other unauthorized actions."}],"metrics":[{"other":{"content":{"namespace":"https://access.redhat.com/security/updates/classification/","value":"Important"},"type":"Red Hat severity rating"}},{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":7.1,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"REQUIRED","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N","version":"3.1"},"format":"CVSS"}],"problemTypes":[{"descriptions":[{"cweId":"CWE-625","description":"Permissive Regular Expression","lang":"en","type":"CWE"}]}],"references":[{"tags":["vdb-entry","x_refsource_REDHAT"],"url":"https://access.redhat.com/security/cve/CVE-2026-40110"},{"name":"RHBZ#2466912","tags":["issue-tracking","x_refsource_REDHAT"],"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2466912"},{"tags":["x_sadp-csaf-vex"],"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40110.json"}],"timeline":[{"lang":"en","time":"2026-05-05T22:01:09.643Z","value":"Reported to Red Hat."},{"lang":"en","time":"2026-05-05T21:29:31.323Z","value":"Made public."}],"title":"jupyter-server: Jupyter Server: Cross-Origin Resource Sharing (CORS) bypass via improper Origin header validation","workarounds":[{"lang":"en","value":"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."}],"x_adpType":"supplier","x_generator":{"engine":"sadp-cli 1.0.0"},"providerMetadata":{"orgId":"0b0ca135-0b70-47e7-9f44-1890c2a1c46c","shortName":"redhat-SADP","dateUpdated":"2026-06-30T12:08:58.866Z"}}]}}