CVE-2026-102831 JupyterLab - Stored XSS

JupyterLab 4.5.0 to 4.5.11 and 4.6.4, Notebook 7.5.0 to 7.6.3, and JupyterLite Core 0.7.0 to 0.8.4 contain a stored XSS caused by improper clearing of metadata.trusted in clipboard cell-paste path, letting authenticated attackers execute scripts in the JupyterLab origin, exploit requires useSystemClipboardForCells enabled and pasteCodeCellsWithoutOutput disabled.

CVSS base score 8.1 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Not required
EPSS
0.20% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Stored XSS
Impact
Client Script Exec
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
Published
29 September 2026
Updated
15 October 2026
Weakness
CWE-79

Vendor fix

Update to JupyterLab 4.5.11 or 4.6.4, Notebook 7.6.3, and JupyterLite Core 0.8.4.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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