{"id":"GHSA-vmhf-c436-hxj4","summary":"JupyterLab: Stored XSS in extension manager through package metadata unsanitized URI protocol","details":"A malicious PyPI package can place a `javascript:` URL in its `[project.urls]` metadata. JupyterLab's Extension Manager renders this as the extension's home-page link without validating the protocol, so a user who clicks the extension name executes attacker-controlled JavaScript in the JupyterLab origin.\n\n### Details\n\nOne of the PyPI package's URL (jupyterlab/extensions/pypi.py) is copied straight into the `homepage_url` rendered by the frontend in packages/extensionmanager/src/widget.tsx#L77-L88.\n\n```python\nbest_guess_home_url = (\n    homepage_url            # home_page / [project.urls] Homepage\n    or data.get(\"project_url\")\n    or data.get(\"package_url\")\n    or documentation_url    # docs_url / [project.urls] Documentation\n    or source_url           # [project.urls] Source Code\n    or bug_tracker_url      # bugtrack_url / [project.urls] Bug Tracker\n)\n\n# homepage_url=best_guess_home_url\n```\n\n```tsx\n{entry.homepage_url ? (\n  \u003ca href={entry.homepage_url} target=\"_blank\" rel=\"noopener noreferrer\" ...\u003e\n    {entry.name}\n  \u003c/a\u003e\n) : ( \u003cdiv\u003e{entry.name}\u003c/div\u003e )}\n```\n\n### Impact\n\nAn attacker needs to publish a package to PyPI (no access to the target). When the package appears in a victim's extension manager list and the victim clicks the extension name, the payload runs in the JupyterLab origin.\n\nPreconditions: Extension Manager enabled with the default PyPI source, the malicious package appears in the victim's list/search results.\n\n### Patches\nPatched in [4.5.9](https://github.com/jupyterlab/jupyterlab/releases/tag/v4.5.9), commits [4e61e07](https://github.com/jupyterlab/jupyterlab/commit/4e61e07d0a91145b53fbf96ac74b0387f6bc51f6) and [d5d961f](https://github.com/jupyterlab/jupyterlab/commit/d5d961f6e10a6442dddbf94d9a976b3897055a12)","aliases":["CVE-2026-67338"],"modified":"2026-09-10T03:51:09.607910503Z","published":"2026-06-19T15:11:17Z","database_specific":{"nvd_published_at":null,"cwe_ids":["CWE-84"],"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2026-06-19T15:11:17Z"},"references":[{"type":"WEB","url":"https://github.com/jupyterlab/jupyterlab/security/advisories/GHSA-vmhf-c436-hxj4"},{"type":"WEB","url":"https://github.com/jupyterlab/jupyterlab/commit/4e61e07d0a91145b53fbf96ac74b0387f6bc51f6"},{"type":"WEB","url":"https://github.com/jupyterlab/jupyterlab/commit/d5d961f6e10a6442dddbf94d9a976b3897055a12"},{"type":"PACKAGE","url":"https://github.com/jupyterlab/jupyterlab"},{"type":"WEB","url":"https://github.com/jupyterlab/jupyterlab/releases/tag/v4.5.9"}],"affected":[{"package":{"name":"jupyterlab","ecosystem":"PyPI","purl":"pkg:pypi/jupyterlab"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.5.9"}]}],"versions":["0.0.1","0.0.10","0.0.13","0.0.2","0.0.3","0.0.4","0.0.5","0.0.6","0.0.7","0.0.8","0.0.9","0.1.1","0.1.2","0.10.0","0.11.0","0.11.1","0.11.2","0.11.3","0.12.0","0.12.1","0.13.0","0.13.1","0.13.2","0.14.0","0.15.0","0.15.1","0.16.0","0.16.2","0.17.0","0.17.1","0.17.2","0.17.4","0.17.5","0.18.0","0.18.0.dev1","0.18.1","0.19.0","0.2.0","0.20.0","0.20.0rc1","0.20.1","0.20.2","0.20.3","0.20.4","0.21.0","0.21.0rc1","0.21.0rc2","0.21.0rc3","0.21.0rc4","0.21.0rc5","0.22.0","0.22.0rc0","0.22.1","0.23.0","0.23.0rc0","0.23.0rc1","0.23.1","0.23.2","0.24.0","0.24.0rc0","0.24.0rc1","0.24.0rc2","0.24.1","0.25.0","0.25.0rc0","0.25.0rc1","0.25.1","0.25.2","0.25.2rc0","0.26.0","0.26.0rc0","0.26.0rc1","0.26.1","0.26.2","0.26.3","0.26.4","0.26.5","0.27.0","0.27.0rc0","0.27.0rc1","0.27.0rc2","0.27.0rc3","0.27.0rc4","0.27.0rc5","0.27.1","0.27.2","0.28.0","0.28.0rc0","0.28.0rc1","0.28.0rc2","0.28.0rc3","0.28.1","0.28.10","0.28.11","0.28.12","0.28.13","0.28.14","0.28.15","0.28.2","0.28.3","0.28.4","0.28.5","0.28.6","0.28.7","0.28.8","0.29.0","0.29.0rc0","0.29.1","0.29.2","0.3.0","0.30.0","0.30.0rc0","0.30.0rc1","0.30.1","0.30.2","0.30.3","0.30.4","0.30.5","0.30.6","0.31.0","0.31.0rc0","0.31.0rc1","0.31.0rc2","0.31.1","0.31.10","0.31.11","0.31.12","0.31.2","0.31.3","0.31.4","0.31.5","0.31.6","0.31.7","0.31.8","0.31.9","0.32.0","0.32.0rc0","0.32.0rc1","0.32.1","0.33.0","0.33.0rc0","0.33.0rc1","0.33.1","0.33.10","0.33.11","0.33.12","0.33.2","0.33.3","0.33.4","0.33.5","0.33.6","0.33.7","0.33.8","0.33.9","0.34.0","0.34.0rc0","0.34.0rc1","0.34.0rc2","0.34.1","0.34.10","0.34.11","0.34.12","0.34.2","0.34.3","0.34.4","0.34.5","0.34.6","0.34.7","0.34.8","0.34.9","0.35.0","0.35.0rc0","0.35.0rc1","0.35.0rc2","0.35.1","0.35.2","0.35.3","0.35.4","0.35.5","0.35.6","0.4.0","0.4.1","0.5.0","0.6.0","0.7.0","0.8.0","0.9.0","0.9.1","1.0.0","1.0.0a0","1.0.0a1","1.0.0a10","1.0.0a2","1.0.0a3","1.0.0a4","1.0.0a5","1.0.0a6","1.0.0a7","1.0.0a8","1.0.0a9","1.0.0rc0","1.0.0rc1","1.0.1","1.0.10","1.0.2","1.0.3","1.0.4","1.0.5","1.0.6","1.0.7","1.0.9","1.1.0","1.1.0a0","1.1.0a1","1.1.0a2","1.1.0rc0","1.1.1","1.1.2","1.1.3","1.1.4","1.1.5","1.2.0","1.2.0a0","1.2.0a1","1.2.0a2","1.2.0a3","1.2.0rc0","1.2.1","1.2.10","1.2.11","1.2.12","1.2.13","1.2.14","1.2.15","1.2.16","1.2.17","1.2.18","1.2.19","1.2.2","1.2.20","1.2.21","1.2.3","1.2.4","1.2.5","1.2.6","1.2.7","1.2.8","1.2.9","2.0.0","2.0.0a0","2.0.0a1","2.0.0a3","2.0.0a4","2.0.0b1","2.0.0b2","2.0.0b3","2.0.0rc0","2.0.0rc1","2.0.0rc2","2.0.1","2.0.1rc0","2.0.2","2.1.0","2.1.0a0","2.1.0b0","2.1.0rc0","2.1.1","2.1.2","2.1.3","2.1.4","2.1.5","2.2.0","2.2.0a0","2.2.0a1","2.2.0rc1","2.2.1","2.2.10","2.2.2","2.2.4","2.2.5","2.2.6","2.2.7","2.2.8","2.2.9","2.3.0","2.3.0a0","2.3.0a1","2.3.0a2","2.3.0rc0","2.3.1","2.3.2","3.0.0","3.0.0a0","3.0.0a10","3.0.0a11","3.0.0a12","3.0.0a13","3.0.0a14","3.0.0a3","3.0.0a4","3.0.0a5","3.0.0a6","3.0.0a7","3.0.0a8","3.0.0a9","3.0.0b1","3.0.0b2","3.0.0b3","3.0.0b4","3.0.0b6","3.0.0b7","3.0.0b8","3.0.0rc0","3.0.0rc1","3.0.0rc10","3.0.0rc11","3.0.0rc12","3.0.0rc13","3.0.0rc14","3.0.0rc15","3.0.0rc2","3.0.0rc3","3.0.0rc4","3.0.0rc5","3.0.0rc6","3.0.0rc7","3.0.0rc8","3.0.0rc9","3.0.1","3.0.10","3.0.11","3.0.12","3.0.13","3.0.14","3.0.15","3.0.16","3.0.17","3.0.18","3.0.2","3.0.3","3.0.4","3.0.5","3.0.6","3.0.7","3.0.8","3.0.9","3.1.0","3.1.0a0","3.1.0a1","3.1.0a10","3.1.0a11","3.1.0a12","3.1.0a13","3.1.0a2","3.1.0a3","3.1.0a4","3.1.0a5","3.1.0a6","3.1.0a7","3.1.0a8","3.1.0a9","3.1.0b0","3.1.0b1","3.1.0rc1","3.1.0rc2","3.1.1","3.1.10","3.1.11","3.1.12","3.1.13","3.1.14","3.1.16","3.1.17","3.1.18","3.1.19","3.1.2","3.1.4","3.1.6","3.1.7","3.1.8","3.1.9","3.2.0","3.2.0a0","3.2.0a1","3.2.0b0","3.2.0rc0","3.2.1","3.2.2","3.2.3","3.2.4","3.2.5","3.2.6","3.2.7","3.2.8","3.2.9","3.3.0","3.3.0a1","3.3.0a2","3.3.0a3","3.3.0b0","3.3.0rc0","3.3.1","3.3.2","3.3.3","3.3.4","3.4.0","3.4.0a0","3.4.0b0","3.4.0rc0","3.4.1","3.4.2","3.4.3","3.4.4","3.4.5","3.4.6","3.4.7","3.4.8","3.5.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