CVEvulnerability

CVE-2026-6657

8.8 HIGH Published 2026-06-03 Modified 2026-07-21 Official page ↗
Status
Analyzed
Published
2026-06-03
Last modified
2026-07-21
Assigner
[email protected]
CVSS 3.1 ([email protected])
8.8 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS 3.0 ([email protected])
6.1 MEDIUM — CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Weaknesses
CWE-346

Description

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 configurations

• jupyter jupyter server (>= 1.12.0 <= 2.17.0)

Related

Weakness · CWE (1)

  • CWE-346 Origin Validation Error weakness

References