Which versions of SiYuan are affected by CVE-2026-59833?

SiYuan versions before 3.7.1 contain a vulnerability in its Markdown rendering engine that enables arbitrary operating system code execution when users open crafted documents through previews or…

How to fix or mitigate CVE-2026-59833?

Within 24 hours: Audit inventory of all SiYuan deployments and document versions below 3.7.1; disable Bazaar package repository access and document preview rendering in application settings. Within 7 days: Restrict SiYuan usage to internal content sources only and suspend external document imports and exports until vendor patch is released. Within 30 days: Monitor for suspicious command execution and establish upgrade plan for SiYuan 3.7.1 or later.

SiYuan CVE-2026-59833

Q: What is the CVSS score of CVE-2026-59833?

CVE-2026-59833 has a CVSS 4.0 base score of 8.6 (High). CVSS vector: 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.4%.

HIGH

Cross-site Scripting (XSS) (CWE-79)

2026-07-09 GitHub_M

XSS Siyuan Siyuan Note

8.6

CVSS 4.0 · Vendor: GitHub_M

Severity by source

Vendor (GitHub_M) PRIMARY

8.6 HIGH

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

vuln.today AI

8.8 HIGH

Network-delivered stored XSS needs no privileges (PR:N) but requires the victim to open a render path (UI:R); Electron OS command execution gives high C/I/A within the app (S:U, matching vendor SC:N).

3.1 AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

4.0 AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Primary rating from Vendor (GitHub_M).

CVSS VectorVendor: GitHub_M

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Scope

Lifecycle Timeline

Analysis Generated

Jul 09, 2026 - 23:26 vuln.today

DescriptionCVE.org

SiYuan is an open-source personal knowledge management system. Prior to 3.7.1, SiYuan renders note and package content to HTML through the Lute engine with sanitization enabled, but Lute's dangerous javascript scheme block does not check form action or SVG xlink:href attributes, allowing stored cross-site scripting in document export-preview and Bazaar package README render paths that can execute OS commands in the Electron desktop renderer. This issue is fixed in versions 3.7.1.

AnalysisAI

Stored cross-site scripting in SiYuan before 3.7.1 escalates to OS command execution inside the Electron desktop renderer because the bundled Lute Markdown/HTML engine sanitizes content but fails to block dangerous javascript schemes in form action and SVG xlink:href attributes. An attacker who plants crafted content that a victim later opens via document export-preview or a Bazaar package README render can run arbitrary code on the victim's machine. There is no public exploit identified at time of analysis, and it is not on CISA KEV; the CVSS 4.0 base score is 8.6.

Technical ContextAI

SiYuan is a self-hosted, Electron-based personal knowledge management application that converts Markdown notes and marketplace (Bazaar) package content into HTML using the Lute engine with sanitization enabled. The flaw is a CWE-79 (Improper Neutralization of Input During Web Page Generation) sanitizer bypass: Lute's routine that strips dangerous javascript: schemes does not inspect the action attribute of form elements or the xlink:href attribute of SVG elements, so script payloads survive sanitization. Because the rendered HTML is displayed inside the Electron/Chromium renderer - which, unlike a sandboxed browser tab, can reach Node/OS integration in a desktop app - the resulting stored XSS can pivot from in-page script execution to operating-system command execution. The affected component is identified in CPE as cpe:2.3:a:siyuan-note:siyuan:*:*:*:*:*:*:*:* (all versions prior to 3.7.1).

RemediationAI

Upgrade to SiYuan v3.7.1 or later, which contains the Lute sanitization fix (Vendor-released patch: 3.7.1); the corrective change is commit ebe252e61fb93f258d083b9da0fa403679fdf94a and the advisory is GHSA-97xv-3v84-h358. Until upgrading, reduce exposure by not importing or previewing notes and documents from untrusted sources and by avoiding installation of Bazaar packages of unknown provenance, since these are the exact render paths that execute the payload - the trade-off is loss of the preview/marketplace convenience for content you cannot vouch for. Because the escalation to OS command execution depends on the Electron renderer, disabling or refraining from Bazaar package installation removes the marketplace README vector but not the general export-preview vector, so prompt upgrade to 3.7.1 remains the only comprehensive fix.