PT-2026-45961 · Jupyter · Jupyter/Jupyter

Published 2026-06-03 · Updated 2026-06-03 · CVE-2026-6657

NVD

CVSS v3.1

6.1

Medium

Base vector

AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

A vulnerability in jupyter-server versions 1.12.0 through 2.17.0 allows an attacker to bypass CORS origin validation when the allow origin pat configuration is used. The issue arises from the use of re.match() for validating the Origin header, which only anchors at the start of the string. This allows attacker-controlled domains such as trusted.example.com.evil.com to pass validation against patterns intended to match trusted.example.com. The vulnerability affects multiple locations in the codebase, including CORS headers, WebSocket connections, referer validation, and login redirects, potentially enabling phishing attacks, arbitrary code execution, and unauthorized access to sensitive API responses.

Fix

Origin Validation Error

Weakness Enumeration

CWE-346

Related Identifiers

CVE-2026-6657

Affected Products

Jupyter/Jupyter

References · 2

• https://nvd.nist.gov/vuln/detail/CVE-2026-6657 · Security Note
• https://huntr.com/bounties/18f642db-3569-43b3-b58d-ff97be4b09d7 · Note