SB20260505104 - Multiple vulnerabilities in Jupyter Server

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Main Vulnerability Database SB20260505104

SB20260505104 - Multiple vulnerabilities in Jupyter Server

Published: May 5, 2026

Security Bulletin ID SB20260505104
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 3
Exploitation vector Remote access
Highest impact Information disclosure

Breakdown by Severity

Medium 67% Low 33%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 3 vulnerabilities.


1) Regular Expression without Anchors (CVE-ID: CVE-2026-40110)

The vulnerability allows a remote attacker to disclose sensitive information and modify data.

The vulnerability exists due to regular expression without anchors in the allow_origin_pat Origin header validation when validating cross-origin requests. A remote attacker can use a controlled domain that prefixes a trusted origin to bypass validation and disclose sensitive information and modify data.

User interaction is required.


2) Insufficient Session Expiration (CVE-ID: CVE-2026-40934)

The vulnerability allows a remote user to maintain indefinite authenticated access.

The vulnerability exists due to insufficient session expiration in the authentication cookie handling when reusing previously issued authentication cookies after a password reset and server restart. A remote user can reuse a stolen or compromised authentication cookie to maintain indefinite authenticated access.

The issue affects deployments using password authentication.


3) Open redirect (CVE-ID: CVE-2025-61669)

The vulnerability allows a remote attacker to redirect users to arbitrary external domains.

The vulnerability exists due to url redirection to an untrusted site in LoginFormHandler._redirect_safe() when processing the next query parameter. A remote attacker can supply a crafted next parameter to redirect users to arbitrary external domains.

User interaction is required for a victim to follow the crafted login URL.


Remediation

Install update from vendor's website.

References