CVE-2026-40110

Fixed in a distro release EPSS <1%CVSS 7.6

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.

Published 2026-05-05 · CVE record · OSV

Products: jupyter-server jupyter_server, Red Hat Migration Toolkit for Applications 8.2, Red Hat OpenShift AI (RHOAI)

Fixed upstream

Distro releases