{"id":"OESA-2026-3956","summary":"python-jupyter-server security update","details":"The backend for Jupyter web applications\r\n\r\nSecurity Fix(es):\n\nThe nbconvert HTTP handlers in jupyter_server render user-authored notebook HTML under the Jupyter origin without a sandbox directive in their `Content-Security-Policy`. Combined with `nbconvert.HTMLExporter`'s default non-sanitizing behavior, a notebook carrying an HTML payload in a display_data output triggers stored XSS with cookie access, full /api/* authority, and kernel RCE. An authenticated victim who navigates to `/nbconvert/html/<path>` containing attacker-authored output can have their token exfiltrated to another domain because it is executed in the Jupyter origin.(CVE-2026-44727)","modified":"2026-09-20T13:30:30.305236853Z","published":"2026-09-20T13:23:34Z","upstream":["CVE-2026-44727"],"database_specific":{"severity":"Critical"},"references":[{"type":"ADVISORY","url":"https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-3956"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44727"}],"affected":[{"package":{"name":"python-jupyter-server","ecosystem":"openEuler:24.03-LTS-SP4","purl":"pkg:rpm/openEuler/python-jupyter-server&distro=openEuler-24.03-LTS-SP4"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.13.0-3.oe2403sp4"}]}],"ecosystem_specific":{"noarch":["python3-jupyter-server-2.13.0-3.oe2403sp4.noarch.rpm"],"src":["python-jupyter-server-2.13.0-3.oe2403sp4.src.rpm"]},"database_specific":{"source":"https://repo.openeuler.org/security/data/osv/OESA-2026-3956.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"}]}