CVE catalog

CVE-2026-40110

Severity: High · CVSS 7.6
Published: May 5, 2026, 4:54:31 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.31% · Oct 25, 2026

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.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	jupyter-server	sid	`2.20.0-3`	fixed
Debian	jupyter-server	forky	`2.20.0-3`	fixed
Debian	jupyter-server	trixie	`2.15.0-1`	vulnerable
Debian	jupyter-server	bookworm	`1.23.3-1`	vulnerable
Cpe	jupyter-server	Not reported	Not reported	vulnerable
Cpe	jupyter_server	Not reported	`2.18.0`	fixed
PyPI	jupyter-server	Not reported	`2.18.0`	fixed
PyPI	jupyter-server	Not reported	`2.18.0`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	jupyter-server	source	sid	`2.20.0-1`	not yet assigned	Not reported	[1136022]
Debian	jupyter-server	source	forky	`2.20.0-1`	not yet assigned	Not reported	[1136022]
Debian	jupyter-server	source	trixie	`(unfixed)`	not yet assigned	Not reported	[1136022]
Debian	jupyter-server	source	bookworm	`(unfixed)`	not yet assigned	Not reported	[1136022]
Cpe	jupyter_server	cpe	Not reported	`2.18.0`	Not reported	Not reported	Not reported
PyPI	jupyter-server	PyPI	Not reported	`2.18.0`	Not reported	GHSA-24QX-W28J-9M6P	Not reported
PyPI	jupyter-server	PyPI	Not reported	`2.18.0`	Not reported	PYSEC-2026-2187	Not reported

[Debian bug #1136022]

Notes

[trixie] jupyter-server: Minor issue [bookworm] jupyter-server: Minor issue; unanchored allow_origin_pat re.match present, revisit with next update

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[jupyter-server]Affected
Details (2)
- 1.23.3-1 · all · bookworm
  Affected
  nvd · jupyter-server · debian · bookworm; nvd · jupyter-server · debian · 12
- 1.23.3-1 · all · bookworm
  Affected
  nvd · jupyter-server · debian · bookworm; nvd · jupyter-server · debian · 12
[python3-jupyter-server]Affected
Source package: [jupyter-server]
Details (2)
- 1.23.3-1 · all · bookworm
  Affected
  nvd · jupyter-server · debian · bookworm; nvd · jupyter-server · debian · 12
- 1.23.3-1 · all · bookworm
  Affected
  nvd · jupyter-server · debian · bookworm; nvd · jupyter-server · debian · 12

[Debian 13 (Trixie)]

[jupyter-server]Affected
Details (2)
- 2.15.0-1 · all · trixie
  Affected
  nvd · jupyter-server · debian · 13
- 2.15.0-1 · all · trixie
  Affected
  nvd · jupyter-server · debian · 13
[python3-jupyter-server]Affected
Source package: [jupyter-server]
Details (2)
- 2.15.0-1 · all · trixie
  Affected
  nvd · jupyter-server · debian · 13
- 2.15.0-1 · all · trixie
  Affected
  nvd · jupyter-server · debian · 13
[python-jupyter-server-doc]Affected
Source package: [jupyter-server]
Details (2)
- 2.15.0-1 · all · trixie
  Affected
  nvd · jupyter-server · debian · 13
- 2.15.0-1 · all · trixie
  Affected
  nvd · jupyter-server · debian · 13

Observed: Oct 23, 2026, 10:21:37 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]