{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-54701","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-06-15T22:58:06.563Z","datePublished":"2026-10-14T19:11:51.712Z","dateUpdated":"2026-10-20T02:01:15.836Z"},"containers":{"cna":{"title":"Markdown Preview Enhanced: Stored XSS via Unsanitized `.crossnote/head.html` Injection in Webview","problemTypes":[{"descriptions":[{"cweId":"CWE-79","lang":"en","description":"CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')","type":"CWE"}]}],"metrics":[{"cvssV4_0":{"attackVector":"LOCAL","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"PASSIVE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"HIGH","vulnAvailabilityImpact":"LOW","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":6.9,"baseSeverity":"MEDIUM","vectorString":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N","version":"4.0"}}],"references":[{"name":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-mcwg-4j78-qwv3","tags":["x_refsource_CONFIRM"],"url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-mcwg-4j78-qwv3"},{"name":"https://github.com/shd101wyy/crossnote/pull/444","tags":["x_refsource_MISC"],"url":"https://github.com/shd101wyy/crossnote/pull/444"},{"name":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2323","tags":["x_refsource_MISC"],"url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/pull/2323"},{"name":"https://github.com/shd101wyy/crossnote/commit/8c55a2ba3365712a1caa4abeece0383bc2994d48","tags":["x_refsource_MISC"],"url":"https://github.com/shd101wyy/crossnote/commit/8c55a2ba3365712a1caa4abeece0383bc2994d48"},{"name":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/8bc848b6cbb42b9f35a0f95f7c3bf29b8302970e","tags":["x_refsource_MISC"],"url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/commit/8bc848b6cbb42b9f35a0f95f7c3bf29b8302970e"},{"name":"https://github.com/shd101wyy/crossnote/releases/tag/0.9.31","tags":["x_refsource_MISC"],"url":"https://github.com/shd101wyy/crossnote/releases/tag/0.9.31"},{"name":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.30","tags":["x_refsource_MISC"],"url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/releases/tag/0.8.30"}],"affected":[{"vendor":"shd101wyy","product":"vscode-markdown-preview-enhanced","versions":[{"version":"< 0.8.30","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-10-14T19:11:51.712Z"},"descriptions":[{"lang":"en","value":"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."}],"source":{"advisory":"GHSA-mcwg-4j78-qwv3","discovery":"UNKNOWN"}},"adp":[{"references":[{"url":"https://github.com/shd101wyy/vscode-markdown-preview-enhanced/security/advisories/GHSA-mcwg-4j78-qwv3","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-20T02:00:52.506160Z","id":"CVE-2026-54701","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-10-20T02:01:15.836Z"}}]}}