{"schema_version":"1","data":[{"id":3311,"advisory_id":"35565c31-6c5d-4404-8d06-ceabadb49731","revision":1,"source_id":"core-cve","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-100639","source_published_at":"2026-09-26T13:23:12.602+00:00","published_at":"2026-10-24T21:33:26.690566+00:00","extraction_method":"structured","technologies":["core-cve","siyuan"],"cve_ids":["CVE-2026-100639"],"event_types":["advisory"],"payload":{"kind":"advisory","title":"SiYuan before v3.8.4 Cross-Site Scripting via Kramdown IAL","summary":"SiYuan v3.8.3 fails to HTML-escape the data-subtype attribute when generating gutter-button markup (app/src/protyle/gutter/button.ts, assigned via innerHTML in app/src/protyle/gutter/index.ts) from content pasted as plain-text Markdown containing a Kramdown inline attribute list (IAL). Because the shared Lute renderer parses Kramdown IAL from text/plain input, an attacker-supplied Markdown snippet using entity-encoded quotes in data-subtype breaks out of the attribute value when the gutter markup is re-parsed by the browser, injecting additional attributes such as autofocus and onfocus. If a victim pastes the crafted Markdown and the affected gutter control receives focus, the injected handler executes; in the Electron desktop application, where the main BrowserWindow enables Node integration and disables context isolation, this results in JavaScript execution with renderer Node.js privileges (remote code execution). Fixed in v3.8.4.","evidence":"cve:CVE-2026-100639","products":[{"name":{"value":"siyuan","evidence":"/containers/cna/affected/0/product"},"prerequisites":[],"fixed_versions":[],"affected_versions":[]}],"severity":"high","structured":{"id":"CVE-2026-100639","aliases":["CVE-2026-100639"],"metrics":[{"format":"CVSS","cvssV4_0":{"version":"4.0","baseScore":8.6,"attackVector":"NETWORK","baseSeverity":"HIGH","vectorString":"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","userInteraction":"ACTIVE","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","subIntegrityImpact":"NONE","vulnIntegrityImpact":"HIGH","subAvailabilityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","vulnConfidentialityImpact":"HIGH"}},{"format":"CVSS","cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":8.8,"attackVector":"NETWORK","baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H","integrityImpact":"HIGH","userInteraction":"REQUIRED","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"NONE","confidentialityImpact":"HIGH"}}],"affected":[{"vendor":"siyuan-note","product":"siyuan","versions":[{"status":"affected","version":"0","lessThan":"3.8.4","versionType":"semver"},{"status":"unaffected","version":"3.8.4","versionType":"semver"}],"defaultStatus":"unaffected"}],"modified":"2026-09-28T18:51:14.199Z","provider":"cve","references":["https://github.com/siyuan-note/siyuan/security/advisories/GHSA-2cmm-9x9j-rvff","https://www.vulncheck.com/advisories/siyuan-before-3.8.4-cross-site-scripting-via-kramdown-ial"],"provider_metadata":{"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-100639","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-09-28T18:49:39.724850Z"}}}],"references":[{"url":"https://github.com/siyuan-note/siyuan/security/advisories/GHSA-2cmm-9x9j-rvff","tags":["exploit"]}],"providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-09-28T18:51:14.199Z"}}],"cna":{"orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","shortName":"VulnCheck","dateUpdated":"2026-09-26T13:23:12.602Z"}}},"related_cves":[{"value":"CVE-2026-100639","evidence":"/cveMetadata/cveId"}],"security_relevant":true,"severity_evidence":"/containers/cna/metrics"}}],"next_after":3311,"next_before":3311}