SiYuan Desktop: Stored XSS in imported .sy.zip content leads to arbitrary command execution

Exploitation

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

CVSS

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

EPSS

• CVE-2026-34585: 0.35% estimated exploitation activity in the next 30 days; percentile 28.56 (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 vulnerability allows crafted block attribute values to bypass server-side attribute escaping when an HTML entity is mixed with raw special characters. An attacker can embed a malicious IAL value inside a .sy document, package it as a .sy.zip, and have the victim import it through the normal Import - SiYuan .sy.zip workflow. Once the note is opened, the malicious attribute breaks out of its original HTML context and injects an event handler, resulting in stored XSS. In the Electron desktop client, this XSS reaches remote code execution because injected JavaScript runs with access to Node/Electron APIs. Details The issue is caused by a logic regression in escapeNodeAttributeValues in kernel/filesys/tree.go. Previously, the escaping logic converted node.KramdownIAL with parse.IAL2Map(...) before deciding whether a value needed escaping. That conversion unescaped existing entities first, so mixed values such as: were still recognized as unsafe and escaped correctly. The logic…

Published by the source

1 Apr 2026, 00:05 UTC

Last modified by the source

6 Apr 2026, 16:40 UTC

Source last checked

26 Oct 2026, 15:19 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-ff66-236v-p4fg

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# Patch Next advisory brief: CVE-2026-34585

Advisory: SiYuan Desktop: Stored XSS in imported .sy.zip content leads to arbitrary command execution
IDs: CVE-2026-34585, GHSA-ff66-236v-p4fg
Record: https://patchnext.com/advisories/cve-2026-34585 (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: High (CVSS 8.6)
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 0.0.0-20260329142331-918d1bd9f967. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/siyuan-note/siyuan/kernel: affected < 0.0.0-20260329142331-918d1bd9f967; fixed in 0.0.0-20260329142331-918d1bd9f967

## 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-ff66-236v-p4fg (GitHub-reviewed advisory GHSA-ff66-236v-p4fg lists affected ranges: Go github.com/siyuan-note/siyuan/kernel >=0 <0.0.0-20260329142331-918d1bd9f967)

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