PyPI/jupyter-server CVE-2026-44727: unknown, EPSS 0.44%

Jupyter Server: Stored XSS in `NbconvertFileHandler` / `NbconvertPostHandler` via missing `sandbox` CSP

Action: Upgrade jupyter-server to 2.20.0 or later.

pip install jupyter-server==2.20.0

Affected

Fixed versions

Sources

• osv: PYSEC-2026-366
• https://github.com/jupyter-server/jupyter_server/security/advisories/GHSA-fcw5-x6j4-ccmp
• https://github.com/jupyter-server/jupyter_server/commit/6cbee8d65e71abac851c4492fea987ad080580bd
• https://github.com/jupyter-server/jupyter_server
• https://pypi.org/project/jupyter-server
• https://github.com/advisories/GHSA-fcw5-x6j4-ccmp
• https://nvd.nist.gov/vuln/detail/CVE-2026-44727

CVE-2026-44727 · published 2026-06-29T11:50:52.185377Z · modified 2026-07-13T16:15:26.841396760Z · JSON