Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
AV AC PR UI S C I A CVSS EPSS %ile KEV N L N R U H H H 8.8 .0020 9.8 —
AFFECTED Product Versions Fixed jupyter/jupyter unspecified – —
TIMELINE Apr 20 Reserved by @huntr_ai Jun 3 EXPLOIT PUBLISHED — CVE-2026-6657 (jupyter/jupyter). Public exploit reference added. Jun 3 Published (CNA: @huntr_ai)
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.
| Date | Event | Detail |
|---|---|---|
| April 20, 2026 | Reserved | Reserved by @huntr_ai |
| June 3, 2026 | EXPLOIT PUBLISHED | EXPLOIT PUBLISHED — CVE-2026-6657 (jupyter/jupyter). Public exploit reference added. |
| June 3, 2026 | Published | Published (CNA: @huntr_ai) |
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
|---|---|---|---|---|
| jupyter | jupyter/jupyter | — | unspecified | — |
Authoritative record: CVE-2026-6657 at cve.org
Vendors: jupyter
Weaknesses: CWE-346
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2026-6657 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.