CVSS 4.0
7.6 highCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:L/SC:L/SI:L/SA:LCVE-2026-40110
High (7.6) in jupyter jupyter server. EPSS 0.3% chance of exploitation in the next 30 days. Fixed in jupyter-server 2.18.0.
Jupyter Server is the backend for Jupyter web applications. In versions 2.17.0 and earlier, the Origin header validation uses Python's re.match() to check incoming origins against the allow_origin_pat configuration value. Because re.match() only anchors at the start of the string and does not require a full match, a pattern intended to match only a trusted domain (e.g., trusted.example.com) will also match any origin that begins with that domain followed by additional characters (e.g., trusted.example.com.evil.com). An attacker who controls such a domain can bypass the CORS origin restriction and make cross-origin requests to the Jupyter Server API from an untrusted site. This issue has been fixed in version 2.18.0.
Severity
CVSS 3.1
7.3 highCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N- EPSS
- 0.3% chance of exploitation in the next 30 days; higher than 24% of CVEs (scores of 2026-10-31)
- CWEs
- CWE-777, CWE-625
- Published
- Modified
- Record from
- the NVD, synced
Affected
- jupyter:jupyter_server
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-24qx-w28j-9m6p | PyPI | jupyter-server | <2.18.0 | 2.18.0 |
| PYSEC-2026-2187 | PyPI | jupyter-server | <2.18.0 | 2.18.0 |
References
- https://github.com/jupyter-server/jupyter_server/commit/057869a327c46730afede3eab0ca2d2e3e74acea
- https://github.com/jupyter-server/jupyter_server/commit/49b34392feaa97735b3b777e3baf8f22f2a14ed8
- https://github.com/jupyter-server/jupyter_server/pull/603
- https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-24qx-w28j-9m6p
- https://access.redhat.com/errata/RHSA-2026:43038