Bug 2466810 (CVE-2025-61669)

Summary: CVE-2025-61669 jupyter_server: Jupyter Server: Redirects to arbitrary external domains via insufficient validation of login parameter
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: jkoehler, lphiri, rjohnson
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Jupyter Server. The login flow's `next` query parameter is insufficiently validated, allowing redirects to arbitrary external domains. A remote attacker can exploit this vulnerability by crafting a malicious login URL, which could redirect users to a harmful website and facilitate phishing attacks.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-05-05 17:03:43 UTC
Jupyter Server is the backend for Jupyter web applications. In jupyter_server versions through 2.17.0, the next query parameter in the login flow is insufficiently validated in `LoginFormHandler._redirect_safe()`, which allows redirects to arbitrary external domains via values such as `///example.com`. An attacker can use a crafted login URL to redirect users to a malicious site and facilitate phishing attacks. This issue is fixed in version 2.18.0.