{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:jupyter:notebook:*:*:*:*:*:*:*:*",
            "extracted_events": [
              {
                "introduced": "7.0.0"
              },
              {
                "fixed": "7.5.6"
              }
            ],
            "source": "CPE_RANGE"
          },
          "events": [
            {
              "introduced": "0402c01865da4008ce9b328c1bed5e9d0be1c44b"
            },
            {
              "fixed": "1ab2d2b99261996e94069ca53dd3d74b8b2ee1ba"
            }
          ],
          "repo": "https://github.com/jupyter/notebook",
          "type": "GIT"
        },
        {
          "database_specific": {
            "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"
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "f51404192bf6d0ff79187c884f21e1f91b928146"
            },
            {
              "introduced": "99f973cfb9ddc5ee2e73f69dfb451c6bc8109534"
            },
            {
              "fixed": "e514705afbea2a1096fa2ffe48489c195ff1a4d2"
            }
          ],
          "repo": "https://github.com/jupyterlab/jupyterlab",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-mqcg-5x36-vfcg"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-79"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42557.json"
  },
  "details": "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.",
  "id": "CVE-2026-42557",
  "modified": "2026-08-07T11:31:26.071892228Z",
  "published": "2026-05-13T15:06:14.222Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-42557.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/errata/RHSA-2026:43038"
    },
    {
      "type": "ADVISORY",
      "url": "https://access.redhat.com/security/cve/CVE-2026-42557"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42557.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-mqcg-5x36-vfcg"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-42557"
    },
    {
      "type": "REPORT",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2477086"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "jupyterlab: Command linker attributes in HTML enable one-click command execution from untrusted content"
}