What is CVE-2026-6657?

CVE-2026-6657 is a medium-severity vulnerability in Jupyter Jupyter/jupyter, classified under Origin Validation Error. CVSS score: 6.1/10. Published 2026-06-03.

How severe is CVE-2026-6657?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Vulnerability in Jupyter Jupyter/jupyter

CVE-2026-6657

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 `Origi…

EPSS: 0.000 (6.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

Affected products

Jupyter Jupyter/jupyter — versions unspecified

Weakness classification (CWE)

CWE-346 — Origin Validation Error

References

security@huntr.dev

Frequently asked questions

What is CVE-2026-6657?: CVE-2026-6657 is a medium-severity vulnerability in Jupyter Jupyter/jupyter, classified under Origin Validation Error. CVSS score: 6.1/10. Published 2026-06-03.
How severe is CVE-2026-6657?: Medium severity. CVSS v3 base score is 6.1 out of 10.