How severe is CVE-2025-61669?

CVE-2025-61669 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2025-61669 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-61669?

CVE-2025-61669 affects Jupyter Jupyter Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-61669?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-61669 have an EU (EUVD) identifier?

Yes. CVE-2025-61669 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-209644.

When was CVE-2025-61669 published?

CVE-2025-61669 was published on 2026-05-05 and last updated on 2026-06-17.

CVE-2025-61669

CVE-2025-61669 is a medium-severity vulnerability in Jupyter Jupyter Server with a CVSS 3.x base score of 6.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-601.

Key facts

Severity: Medium (CVSS 3.x base score 6.1)
CVSS v4: 6.3
EPSS exploit prediction: 0% (18th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-209644
Weakness: CWE-601
Affected product: Jupyter Jupyter Server
Published: 2026-05-05
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2025-61669?: 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.
How severe is CVE-2025-61669?: CVE-2025-61669 has a CVSS 3.x base score of 6.1, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2025-61669 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-61669?: CVE-2025-61669 affects Jupyter Jupyter Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-61669?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-61669 have an EU (EUVD) identifier?: Yes. CVE-2025-61669 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-209644.
When was CVE-2025-61669 published?: CVE-2025-61669 was published on 2026-05-05 and last updated on 2026-06-17.

References

https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-qh7q-6qm3-653w

Affected products (1)

cpe:2.3:a:jupyter:jupyter_server:*:*:*:*:*:*:*:*

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Other CWE-601 (Open Redirect) vulnerabilities

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CVE-2025-55031 — Critical (CVSS 9.8): Malicious pages could use Firefox for iOS to pass FIDO: links to the OS and trigger the hybrid passkey transport. An…
CVE-2024-22891 — Critical (CVSS 9.8): Nteract v.0.28.0 was discovered to contain a remote code execution (RCE) vulnerability via the Markdown link.

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Threat intelligence

Threat-intel indicators referencing this CVE:

129.212.181.245 (ipv4-addr)