{"schema":"threatline.record/2","record":{"id":"CVE-2026-54701","aliases":["GHSA-mcwg-4j78-qwv3"],"summary":"Markdown Preview Enhanced: Stored XSS via Unsanitized `.crossnote/head.html` Injection in Webview","details":"Markdown Preview Enhanced is a Markdown preview extension for Visual Studio Code. Prior to 0.8.30, Markdown Preview Enhanced reads repository-controlled .crossnote/head.html content and passes it through resolvePathsInHeader before inserting it into the head of the preview webview document without removing executable content. Script-capable markup executes while the document loads, before the React application and DOMPurify initialize, and can access acquireVsCodeApi to send messages from the webview to the extension host. Opening a Markdown preview in a malicious repository is sufficient to trigger the injected content, and no additional click within the notification or preview is required. This issue is fixed in version 0.8.30.","categories":["Unclassified"],"product":"vscode-markdown-preview-enhanced","vendor":"shd101wyy","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-54701","source_modified_at":"2026-10-20T02:01:15.836Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"vscode-markdown-preview-enhanced","vendor":"shd101wyy","versions":[{"status":"affected","version":"< 0.8.30"}],"defaultStatus":null},{"source":"GitHub Advisory Database","source_url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-mcwg-4j78-qwv3","source_modified_at":"2026-06-16T05:21:49Z","fetched_at":"2026-10-23T20:37:03.234832Z","package":{"name":"vscode-markdown-preview-enhanced","ecosystem":null},"range":"0.8.28"}],"fixed_versions":[],"cvss":6.9,"severity":"Medium","kev":{"listed":false},"epss":{"probability":0.00206,"percentile":0.10204,"score_date":"2026-10-23"},"published_at":"2026-10-14T19:11:51.712Z","modified_at":"2026-10-20T02:01:15.836Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-54701","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-10-20T02:01:15.836Z"},{"source":"GitHub Advisory Database","url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-mcwg-4j78-qwv3","fetched_at":"2026-10-23T20:37:03.234832Z","source_modified_at":"2026-06-16T05:21:49Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-54701","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["CVE List","GitHub Advisory Database","EPSS"],"references":[{"source":"CVE List","url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-mcwg-4j78-qwv3","tags":["exploit"]},{"source":"CVE List","url":"https://github.com/shd101wyy/crossnote/pull/444","tags":["x_refsource_MISC"]},{"source":"CVE List","url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2323","tags":["x_refsource_MISC"]},{"source":"CVE List","url":"https://github.com/shd101wyy/crossnote/commit/8c55a2ba3365712a1caa4abeece0383bc2994d48","tags":["x_refsource_MISC"]},{"source":"CVE List","url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/8bc848b6cbb42b9f35a0f95f7c3bf29b8302970e","tags":["x_refsource_MISC"]},{"source":"CVE List","url":"https://github.com/shd101wyy/crossnote/releases/tag/0.9.31","tags":["x_refsource_MISC"]},{"source":"CVE List","url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.30","tags":["x_refsource_MISC"]}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","cvss_source":"CVE List","ssvc":{"exploitation":"poc","automatable":"no","technical_impact":"partial","assessed_at":"2026-10-20T02:00:52.506160Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":null,"confidence":"unknown","reviewed":false},"change_timestamp":"2026-10-20T02:01:15.836Z","content_hash":"2b57767a52fe304057b8c3dfef8f2f78ea6870ee0de6683fb377a39f692c13d8"}}