CVE-2026-6657
Description
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Mitigation details
CVE-2026-6657 NameCVE-2026-6657 DescriptionA vulnerability in jupyter-server versions 1.12.0 through 2.17.0 allow ... SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) Vulnerable and fixed packages The table below lists information on source packages. Source PackageReleaseVersionStatus…
CVE-2026-6657
| Name | CVE-2026-6657 |
| Description | A vulnerability in jupyter-server versions 1.12.0 through 2.17.0 allow ... |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| jupyter-server (PTS) | bullseye | 1.2.2-1 | vulnerable |
| bookworm | 1.23.3-1 | vulnerable | |
| trixie | 2.15.0-1 | vulnerable | |
| forky, sid | 2.17.0-1 | vulnerable |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| jupyter-server | source | (unstable) | (unfixed) |
Notes
https://huntr.com/bounties/18f642db-3569-43b3-b58d-ff97be4b09d7
Apply commands
https://huntr.com/bounties/18f642db-3569-43b3-b58d-ff97be4b09d7OS impact
Debian Affected 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Affected | — |
| sid | Affected | — |
| forky | Affected | — |
| bullseye | Affected | — |
| bookworm | Affected | — |
References
CWEs
CWE-346
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.