CVE-2026-6657
published 2026-06-03CVE-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…
PriorityP263high8.8CVSS 3.1
AVNACLPRNUIRSUCHIHAH
EPSS
6.18%
93.4th percentile
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
19 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | jupyter-server | 1.12.0 – 2.17.0 | — |
| jupyter | jupyter_jupyter | unspecified – latest | — |
| jupyter | jupyter_server | 1.12.0 – 2.17.0 | — |
| mta | mta-solution-server-rhel9 | — | — |
| rhoai | odh-th06-cpu-torch210-py312-rhel9 | — | — |
| rhoai | odh-th06-cpu-torch291-py312-rhel9 | — | — |
| rhoai | odh-th06-cuda130-torch210-py312-rhel9 | — | — |
| rhoai | odh-th06-cuda130-torch291-py312-rhel9 | — | — |
| rhoai | odh-th06-rocm64-torch291-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-datascience-cpu-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-minimal-cpu-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-minimal-cuda-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-minimal-rocm-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-pytorch-cuda-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-pytorch-llmcompressor-cuda-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-pytorch-rocm-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-tensorflow-cuda-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-tensorflow-rocm-py312-rhel9 | — | — |
| rhoai | odh-workbench-jupyter-trustyai-cpu-py312-rhel9 | — | — |
CVSS provenance
nvdv3.18.8HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
nvdv3.06.1MEDIUMCVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
vendor_redhat6.1MEDIUM
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VulDB
jupyter jupyter-server up to up to 2.17.0 re.match origin validation
vuldb·2026-06-03·CVSS 6.1
CVE-2026-6657 [MEDIUM] jupyter jupyter-server up to up to 2.17.0 re.match origin validation
A vulnerability was found in jupyter jupyter-server up to up to 2.17.0. It has been declared as critical. This affects the function re.match. Such manipulation leads to origin validation error.
This vulnerability is referenced as CVE-2026-6657. It is possible to launch the attack remotely. No exploit is available.
GHSA
jupyter-server is vulnerable to CORS origin validation bypass when the `allow_origin_pat` configuration is used
ghsa·2026-06-03
CVE-2026-6657 [MEDIUM] CWE-346 jupyter-server is vulnerable to CORS origin validation bypass when the `allow_origin_pat` configuration is used
jupyter-server is vulnerable to CORS origin validation bypass when the `allow_origin_pat` configuration is used
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 ac
GHSA
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.
ghsa_unreviewed·2026-06-03
CVE-2026-6657 [MEDIUM] CWE-346 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.
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.
Red Hat
jupyter-server: jupyter-server: Arbitrary code execution due to CORS origin validation bypass
vendor_redhat·2026-06-03·CVSS 6.1
CVE-2026-6657 [MEDIUM] CWE-625 jupyter-server: jupyter-server: Arbitrary code execution due to CORS origin validation bypass
jupyter-server: jupyter-server: Arbitrary code execution due to CORS origin validation bypass
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
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2026-6657 python-jupyter-server: jupyter-server: Arbitrary code execution due to CORS origin validation bypass [epel-all]
bugzilla·2026-06-05·CVSS 6.1
CVE-2026-6657 [MEDIUM] CVE-2026-6657 python-jupyter-server: jupyter-server: Arbitrary code execution due to CORS origin validation bypass [epel-all]
CVE-2026-6657 python-jupyter-server: jupyter-server: Arbitrary code execution due to CORS origin validation bypass [epel-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Bugzilla
CVE-2026-6657 python-jupyter-server: jupyter-server: Arbitrary code execution due to CORS origin validation bypass [fedora-all]
bugzilla·2026-06-05·CVSS 6.1
CVE-2026-6657 [MEDIUM] CVE-2026-6657 python-jupyter-server: jupyter-server: Arbitrary code execution due to CORS origin validation bypass [fedora-all]
CVE-2026-6657 python-jupyter-server: jupyter-server: Arbitrary code execution due to CORS origin validation bypass [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Bugzilla
CVE-2026-6657 jupyter-server: jupyter-server: Arbitrary code execution due to CORS origin validation bypass
bugzilla·2026-06-03·CVSS 6.1
CVE-2026-6657 [MEDIUM] CVE-2026-6657 jupyter-server: jupyter-server: Arbitrary code execution due to CORS origin validation bypass
CVE-2026-6657 jupyter-server: jupyter-server: Arbitrary code execution due to CORS origin validation bypass
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
2026-06-03
Published