CVE-2026-54070
Received Received - Intake
Stored XSS in SiYuan Knowledge Management System

Publication date: 2026-06-24

Last updated on: 2026-06-24

Assigner: GitHub, Inc.

Description
SiYuan is an open-source personal knowledge management system. Prior to 3.7.0, renderPackageREADME in kernel/bazaar/readme.go renders a Bazaar package README from Markdown to HTML with the lute engine and SetSanitize(true). The lute sanitizer is an event-handler blocklist: allowAttr rejects only attribute names present in a fixed eventAttrs map copied from the w3schools legacy handler list. That map omits modern event handlers. onpointerover, onpointerdown, onauxclick, onbeforetoggle, onfocusin, onanimationstart, and ontransitionend are not in the list, so the sanitizer passes them through verbatim on any tag. The frontend assigns the rendered HTML to mdElement.innerHTML in app/src/config/bazaar.ts with no client-side DOMPurify on this path, into a normal element in the main document (no iframe, no sandbox). The kernel sends no Content-Security-Policy, X-Frame-Options, or X-Content-Type-Options header on any response, so an inline handler runs when its event fires. The README is rendered when an Administrator opens a package in Settings → Marketplace, after the one-time marketplace trust consent. Install is not required. Result: a third-party Bazaar package author runs JavaScript in the Administrator's authenticated SiYuan origin when the Administrator views and interacts with the package listing, and gains full control of the workspace. This vulnerability is fixed in 3.7.0.
CVSS Scores
EPSS Scores
Probability:
Percentile:
Meta Information
Published
2026-06-24
Last Modified
2026-06-24
Generated
2026-06-25
AI Q&A
2026-06-25
EPSS Evaluated
N/A
NVD
CVE-2026-54070
Affected Vendors & Products
Currently, no data is known.
Helpful Resources
Exploitability
CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-79 The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
CWE-184 The product implements a protection mechanism that relies on a list of inputs (or properties of inputs) that are not allowed by policy or otherwise require other action to neutralize before additional processing takes place, but the list is incomplete.
Attack-Flow Graph
AI Quick Actions
Instant insights powered by AI
Executive Summary

This vulnerability exists in SiYuan, an open-source personal knowledge management system, prior to version 3.7.0. The issue is in how the system renders Bazaar package README files from Markdown to HTML using the lute engine with a sanitizer that only blocks a fixed list of legacy event handler attributes. Modern event handlers like onpointerover, onpointerdown, and others are not blocked and are passed through verbatim.

Because the frontend assigns this rendered HTML directly to an element's innerHTML without additional client-side sanitization or security headers, a malicious third-party Bazaar package author can inject JavaScript event handlers. When an Administrator views and interacts with the package listing, this JavaScript runs with the Administrator's authenticated privileges, allowing full control over the workspace.

This vulnerability is fixed in version 3.7.0.

Impact Analysis

The vulnerability allows a third-party Bazaar package author to execute arbitrary JavaScript code within the context of an authenticated Administrator's session in SiYuan.

This can lead to full compromise of the Administrator's workspace, including unauthorized access, modification, or deletion of data managed by SiYuan.

Because the attack requires the Administrator to view and interact with the malicious package listing, it involves user interaction but can result in high impact due to the elevated privileges.

Mitigation Strategies

To mitigate this vulnerability, upgrade SiYuan to version 3.7.0 or later, where the issue is fixed.

Avoid opening Bazaar package READMEs in the Settings → Marketplace section until the upgrade is applied, especially as an Administrator.

Chat Assistant
Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-54070. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70
EPSS Chart