{
"id": "GHSA-24qx-w28j-9m6p",
"aliases": [
"CVE-2026-40110"
],
"details": "Jupyter Server uses `re.match()` to validate the Origin header against the `allow_origin_pat` configuration.\n\nSince `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`.\n\n### Impact\n\n<=2.17.0\n\n### Patches\n\n057869a327c46730afede3eab0ca2d2e3e74acea, 49b34392feaa97735b3b777e3baf8f22f2a14ed8 \n\n### Workarounds\n\nWrap your `allow_origin_pat` value with `^` and `$`\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",
"summary": "Jupyter Server has a CORS Origin Validation Bypass via `re.match()` in `allow_origin_pat`",
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.18.0"
}
]
}
],
"package": {
"name": "jupyter-server",
"ecosystem": "PyPI"
},
"database_specific": {
"last_known_affected_version_range": "<= 2.17.0"
}
}
],
"modified": "2026-07-31T20:27:11Z",
"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"
}
],
"published": "2026-05-05T16:54:31Z",
"references": [
{
"url": "https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-24qx-w28j-9m6p",
"type": "WEB"
},
{
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-40110",
"type": "ADVISORY"
},
{
"url": "https://github.com/jupyter-server/jupyter_server/pull/603",
"type": "WEB"
},
{
"url": "https://github.com/jupyter-server/jupyter_server/commit/057869a327c46730afede3eab0ca2d2e3e74acea",
"type": "WEB"
},
{
"url": "https://github.com/jupyter-server/jupyter_server/commit/49b34392feaa97735b3b777e3baf8f22f2a14ed8",
"type": "WEB"
},
{
"url": "https://access.redhat.com/errata/RHSA-2026:43038",
"type": "WEB"
},
{
"url": "https://access.redhat.com/security/cve/CVE-2026-40110",
"type": "WEB"
},
{
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2466912",
"type": "WEB"
},
{
"url": "https://github.com/jupyter-server/jupyter_server",
"type": "PACKAGE"
},
{
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/jupyter-server/PYSEC-2026-2187.yaml",
"type": "WEB"
},
{
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-40110.json",
"type": "WEB"
}
],
"schema_version": "1.4.0",
"database_specific": {
"cwe_ids": [
"CWE-625",
"CWE-777"
],
"severity": "HIGH",
"github_reviewed": true,
"nvd_published_at": "2026-05-05T22:16:00Z",
"github_reviewed_at": "2026-05-05T16:54:31Z"
}
}