jupyterlab is an extensible environment for interactive and reproducible computing, based on the Jupyter Notebook Architecture. Prior to 4.5.7, JupyterLab's HTML sanitizer allowlists data-commandlinker-command and data-commandlinker-args on button elements, while CommandLinker listens for all click events on document.body and executes the named command without checking whether the element came from trusted JupyterLab UI. A notebook with a pre-saved HTML cell output containing a deceptive button can trigger arbitrary JupyterLab commands - including arbitrary code execution - on a single user click, without any code being submitted for execution by the user. This vulnerability is fixed in 4.5.7.
{
"cwe_ids": [
"CWE-79"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42557.json",
"cna_assigner": "GitHub_M"
}{
"cpe": "cpe:2.3:a:jupyter:notebook:*:*:*:*:*:*:*:*",
"extracted_events": [
{
"introduced": "7.0.0"
},
{
"fixed": "7.5.6"
}
],
"source": "CPE_RANGE"
}
{
"cpe": [
"cpe:2.3:a:jupyter:jupyterlab:*:*:*:*:*:*:*:*",
"cpe:2.3:a:jupyter:notebook:*:*:*:*:*:*:*:*"
],
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "4.5.7"
},
{
"introduced": "7.0.0"
},
{
"fixed": "7.5.6"
}
],
"source": "CPE_RANGE"
}