CVE catalog

CVE-2026-40934

Severity: High · CVSS 7.6
Published: May 5, 2026, 5:03:24 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.33% · Oct 25, 2026

Jupyter Server is the backend for Jupyter web applications. In versions 2.17.0 and earlier, the secret used to sign authentication cookies is persisted to a static file at ~/.local/share/jupyter/runtime/jupyter_cookie_secret and is never rotated when a user changes their password. After a password reset and server restart, any previously issued authentication cookie remains cryptographically valid because the signing key has not changed. An attacker who has captured a session cookie through any means retains full authenticated access to the server regardless of subsequent password changes. This affects deployments using password-based authentication, particularly shared or public-facing servers where credential rotation is expected to revoke existing sessions. 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-5MRQ-X3X5-8V8F	Not reported
PyPI	jupyter-server	PyPI	Not reported	`2.18.0`	Not reported	PYSEC-2026-69	Not reported

[Debian bug #1136022]

Notes

[trixie] jupyter-server: Minor issue [bookworm] jupyter-server: Minor issue; cookie_secret_file persistence 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]