Vulnerability-Lookup

GHSA-V42X-X7JP-845H

Vulnerability from github – Published: 2026-06-03 18:33 – Updated: 2026-06-03 18:33

Details

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.

Severity

6.1 (Medium)


                  
                    CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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{
  "affected": [],
  "aliases": [
    "CVE-2026-6657"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-346"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-03T16:16:31Z",
    "severity": "MODERATE"
  },
  "details": "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.",
  "id": "GHSA-v42x-x7jp-845h",
  "modified": "2026-06-03T18:33:10Z",
  "published": "2026-06-03T18:33:10Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6657"
    },
    {
      "type": "WEB",
      "url": "https://huntr.com/bounties/18f642db-3569-43b3-b58d-ff97be4b09d7"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-6657 (GCVE-0-2026-6657)

Vulnerability from cvelistv5 – Published: 2026-06-03 15:06 – Updated: 2026-06-03 17:25

Title

CORS Origin Validation Bypass in jupyter-server

Summary

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.

Severity

6.1 (Medium)


                        
                          CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-346 - Origin Validation Error

Assigner

@huntr_ai

References

1 reference

URL	Tags
https://huntr.com/bounties/18f642db-3569-43b3-b58…

Impacted products

1 product

Vendor	Product	Version
jupyter	jupyter/jupyter	Affected: unspecified , ≤ latest (custom)

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JSON

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                "id": "CVE-2026-6657",
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                  },
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                  }
                ],
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                "timestamp": "2026-06-03T17:24:16.863193Z",
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-V42X-X7JP-845H

CVE-2026-6657 (GCVE-0-2026-6657)

Tags

Sightings

Nomenclature