CVE-2026-6657: CORS Origin Validation Bypass in jupyter-server
jupyter · jupyter/jupyter
Affected: jupyter/jupyter · Exploitation: possible (1 to 10%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 92% of scored CVEs
DescriptionCVE.org
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 `Origin` header, which only anchors at the start of the string. This allows attacker-controlled domains such as `trusted.example.com.evil.com` to pass validation against patterns intended to match `trusted.example.com`. The vulnerability affects multiple locations in the codebase, including CORS headers, WebSocket connections, referer validation, and login redirects, potentially enabling phishing attacks, arbitrary code execution, and unauthorized access to sensitive API responses.
Affected products1
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- jupyter · jupyter/jupyterup to and including latest
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CoverageNo articles yet
No CyberSIXT article names CVE-2026-6657 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.