CVE-2026-40864
Description
JupyterHub is software that allows users to create a multi-user server for Jupyter notebooks. In versions 4.1.0 through 5.4.4, XSRF protection (updated in 4.1.0) inappropriately treated requests with Sec-Fetch-Mode: no-cors as same-origin requests, bypassing XSRF checks. The JSON API is not affected, only HTTP form endpoints, such as /hub/spawn and /hub/accept-share, meaning attackers could trigger server spawn (but not access the server) and if the attacker is a JupyterHub user permitted to share access to their server, cause a user to accept a share and have access to the attacker's server. This issue has been fixed in version 5.4.5. If developers are unable to immediately upgrade, they can temporarily mitigate this issue by dropping requests to JupyterHub with Sec-Fetch-Mode: no-cors if they are using a reverse proxy.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
jupyterhubPyPI | >= 4.1.0, < 5.4.5 | 5.4.5 |
Affected products
6>= 4.1.0, < 5.4.5+ 1 more
- (no CPE)range: >= 4.1.0, < 5.4.5
- cpe:2.3:a:jupyter:jupyterhub:*:*:*:*:*:*:*:*range: >=4.1.0,<5.4.5
- osv-coords4 versionspkg:apk/chainguard/py3.11-jupyterhubpkg:apk/wolfi/py3.11-jupyterhubpkg:bitnami/jupyterhubpkg:pypi/jupyterhub
< 5.4.6-r0+ 3 more
- (no CPE)range: < 5.4.6-r0
- (no CPE)range: < 5.4.6-r0
- (no CPE)range: >= 4.1.0, < 5.4.5
- (no CPE)range: >= 4.1.0, < 5.4.5
Patches
Vulnerability mechanics
References
4- github.com/jupyterhub/jupyterhub/commit/9c5ec277d3cda5a59de2d8c8117efa77bd941127nvdPatchWEB
- github.com/advisories/GHSA-m68r-v472-jgq9ghsaADVISORY
- github.com/jupyterhub/jupyterhub/security/advisories/GHSA-m68r-v472-jgq9nvdMitigationVendor AdvisoryWEB
- nvd.nist.gov/vuln/detail/CVE-2026-40864ghsaADVISORY
News mentions
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