CVE-2026-6657

The record

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.

Affected packages

Related vulnerabilities

• CVE-2026-114125 Storybook is a frontend workshop for building user interface components and pages in… CWE-346
• CVE-2026-107230 The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP… CWE-346
• CVE-2026-94485 Next.js is a React framework for building full-stack web applications. CWE-346
• CVE-2026-94486 Next.js is a React framework for building full-stack web applications. CWE-346
• CVE-2026-77119 A validly signed NSEC3 from an unrelated sibling zone may be accepted as an insecurity… CWE-346
• CVE-2026-87563 Origin validation error in Paint in Google Chrome prior to 153.0.8010.36 allowed a remote… CWE-346
• CVE-2026-85152 undici 8.10.0 omits the destination origin from the cache and request-deduplication keys… CWE-346
• CVE-2026-84482 WWBN AVideo through commit 9c39d8c8 contains a cross-site request forgery vulnerability… CWE-346