Medium severity · published May 5, 2026
CVE-2025-61669
jupyter_server next parameter open redirect can redirect users to external domains
6.1
CVSS
0.2%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
Low
Integrity
Low
Availability
None
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 15% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
JU
jupyter_server · jupyter-server
<= 2.17.0 · source: vendor
JS
Jupyter Server · Jupyter
before 2.18.0 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-61669
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-61669
Exploit
https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-qh7q-6qm3-653w
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