Is CVE-2026-40110 actively exploited?

No active exploitation of CVE-2026-40110 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-40110 be exploited remotely?

Yes. CVE-2026-40110 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-40110?

CVE-2026-40110 has a CVSS score of 7.3 (HIGH).

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HIGH

CVE-2026-40110

CWE-777Published: May 5, 2026· Updated: May 11, 2026

7.3

CVSS v3.1

EPSS:0.04%probability of exploitation in 30 daysPercentile:12.7th

Official Description

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.

NVD Source

Technical Analysis

CVE-2026-40110 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires low privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), with a CVSS base score of 7.3.