{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-54067: SiYuan: Stored XSS to RCE via CSS-snippet <style> breakout in renderSnippet()","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-54067","status":"final","version":"1","initial_release_date":"2026-06-24T21:14:38.173Z","current_release_date":"2026-06-24T21:14:38.173Z","revision_history":[{"date":"2026-06-24T21:14:38.173Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"SiYuan is an open-source personal knowledge management system. Prior to 3.7.0, CSS snippet body containing </style> breaks out of its surrounding <style> tag when renderSnippet() interpolates it via insertAdjacentHTML. A payload like runs arbitrary JavaScript in the renderer. On Electron desktop builds the renderer runs with nodeIntegration:true, so require('child_process') is reachable from the injected handler and the XSS chains to host RCE. Snippets sync via the workspace repository, so an attacker with write access to any synced workspace plants the payload once and it fires on every device that pulls. The bug also bypasses the user's enabledCSS / enabledJS separation. A user who turned enabledJS off was making a deliberate call not to run untrusted JavaScript; the CSS path runs it anyway. This vulnerability is fixed in 3.7.0.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-54067 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-54067"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-54067"},{"category":"external","summary":"https://github.com/siyuan-note/siyuan/security/advisories/GHSA-mvjr-vv3c-w4qv","url":"https://github.com/siyuan-note/siyuan/security/advisories/GHSA-mvjr-vv3c-w4qv"}]},"product_tree":{"branches":[{"category":"vendor","name":"siyuan-note","branches":[{"category":"product_name","name":"siyuan","branches":[{"category":"product_version","name":"< 3.7.0","product":{"name":"siyuan-note siyuan < 3.7.0","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:siyuan-note:siyuan:\\<_3.7.0:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-54067","title":"SiYuan: Stored XSS to RCE via CSS-snippet <style> breakout in renderSnippet()","notes":[{"category":"description","text":"SiYuan is an open-source personal knowledge management system. Prior to 3.7.0, CSS snippet body containing </style> breaks out of its surrounding <style> tag when renderSnippet() interpolates it via insertAdjacentHTML. A payload like runs arbitrary JavaScript in the renderer. On Electron desktop builds the renderer runs with nodeIntegration:true, so require('child_process') is reachable from the injected handler and the XSS chains to host RCE. Snippets sync via the workspace repository, so an attacker with write access to any synced workspace plants the payload once and it fires on every device that pulls. The bug also bypasses the user's enabledCSS / enabledJS separation. A user who turned enabledJS off was making a deliberate call not to run untrusted JavaScript; the CSS path runs it anyway. This vulnerability is fixed in 3.7.0.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1"]},"scores":[{"cvss_v3":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","baseScore":9.9,"baseSeverity":"CRITICAL"},"products":["CSAFPID-1"]}],"remediations":[{"category":"none_available","details":"No fixed version is published yet. Monitor the upstream advisory.","product_ids":["CSAFPID-1"]}]}]}