SiYuan: Remote Code Execution in the Electron desktop client via stored XSS in synced table captions

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

9.0 · CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

EPSS

• CVE-2026-39846: 0.54% estimated exploitation activity in the next 30 days; percentile 45.38 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary A malicious note synced to another user can trigger remote code execution in the SiYuan Electron desktop client. The root cause is that table caption content is stored without safe escaping and later unescaped into rendered HTML, creating a stored XSS sink. Because the desktop renderer runs with nodeIntegration enabled and contextIsolation disabled, attacker-controlled JavaScript executes with access to Node.js APIs. In practice, an attacker can import a crafted note into a synced workspace, wait for the victim to sync, and achieve code execution when the victim opens the note. Details The vulnerability exists in the table caption handling path. When a table block is parsed, the caption attribute is saved into the node's IAL properties without proper HTML escaping. Later, during rendering, that value is read back, passed through HTML unescaping, and written directly into the output DOM. This turns an attacker-controlled caption into active HTML inside the rendered note. I…

Published by the source

8 Apr 2026, 15:03 UTC

Last modified by the source

8 Apr 2026, 15:03 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-phhp-9rm9-6gr2

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# Patch Next advisory brief: CVE-2026-39846

Advisory: SiYuan: Remote Code Execution in the Electron desktop client via stored XSS in synced table captions
IDs: CVE-2026-39846, GHSA-phhp-9rm9-6gr2
Record: https://patchnext.com/advisories/cve-2026-39846 (revision 1, source checked 26 Oct 2026, 15:19 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/siyuan-note/siyuan/kernel 0.0.0-20260407035653-2f416e5253f1. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/siyuan-note/siyuan/kernel: affected < 0.0.0-20260407035653-2f416e5253f1; fixed in 0.0.0-20260407035653-2f416e5253f1

## Suggested inspection (read-only)
- Go github.com/siyuan-note/siyuan/kernel: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/siyuan-note/siyuan/kernel.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-phhp-9rm9-6gr2 (GitHub-reviewed advisory GHSA-phhp-9rm9-6gr2 lists affected ranges: Go github.com/siyuan-note/siyuan/kernel >=0 <0.0.0-20260407035653-2f416e5253f1)

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