---
id: CVE-2026-100641
title: >-
  SiYuan before v3.8.4 does not HTML-escape stored flashcard block content
  before interpolating it into the card-manager list markup
summary: >-
  SiYuan before v3.8.4 does not HTML-escape stored flashcard block content
  before interpolating it into the card-manager list markup. Block content
  returned by /api/riff/getRiffCards is inserted into a card item template in
  app/src/card/vi…
severity: high
cvss: 8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H'
cwe:
  - CWE-79
vendor: siyuan-note
product: siyuan
affected:
  - siyuan < 3.8.4
published: '2026-09-26'
updated: '2026-09-26'
sourceUpdated: '2026-09-26T14:16:46.193'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-100641'
references:
  - url: >-
      https://github.com/siyuan-note/siyuan/commit/1ecb1c07de497ff03b585536fe5579291754d96b
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/siyuan-note/siyuan/commit/41b14025b4ac4a8379d1200580344ca18ad152b7
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/siyuan-note/siyuan/commit/48c354e7de130aaada9d7120125bbc768344fd3b
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/siyuan-note/siyuan/commit/8641553a1f07374001902d3ce773285db1292b2d
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/siyuan-note/siyuan/security/advisories/GHSA-2mmf-4xwm-55rm
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/siyuan-before-3.8.4-stored-xss-via-unescaped-flashcard-content
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-26T13:33:20.922Z'
---

## Overview

SiYuan before v3.8.4 does not HTML-escape stored flashcard block content before interpolating it into the card-manager list markup. Block content returned by /api/riff/getRiffCards is inserted into a card item template in app/src/card/viewCards.ts and assigned to listElement.innerHTML, so content such as <img src=invalid onerror=...> becomes an executable event-handler attribute. Because the SiYuan desktop (Electron) main window is created with nodeIntegration enabled and contextIsolation disabled, an administrator who opens the card manager on a workspace containing attacker-supplied flashcard content (for example introduced through contribution or import) executes the attacker's script in a privileged renderer, which can lead to arbitrary code execution on the host. The affected endpoint remains behind authentication and administrator-role checks; this is an untrusted-content-to-privileged-renderer issue, not an authorization bypass.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.