CVE-2026-40322 (GCVE-0-2026-40322)

Vulnerability from cvelistv5 – Published: 2026-04-16 23:00 – Updated: 2026-04-16 23:00
VLAI?
Title
SiYuan: Mermaid `javascript:` Link Injection Leads to Stored XSS and Electron RCE
Summary
SiYuan is an open-source personal knowledge management system. In versions 3.6.3 and below, Mermaid diagrams are rendered with securityLevel set to "loose", and the resulting SVG is injected into the DOM via innerHTML. This allows attacker-controlled javascript: URLs in Mermaid code blocks to survive into the rendered output. On desktop builds using Electron, windows are created with nodeIntegration enabled and contextIsolation disabled, escalating the stored XSS to arbitrary code execution when a victim opens a note containing a malicious Mermaid block and clicks the rendered diagram node. This issue has been fixed in version 3.6.4.
CWE
  • CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
  • CWE-94 - Improper Control of Generation of Code ('Code Injection')
Assigner
Impacted products
Vendor Product Version
siyuan-note siyuan Affected: < 3.6.4
Create a notification for this product.
Show details on NVD website

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "siyuan",
          "vendor": "siyuan-note",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 3.6.4"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "SiYuan is an open-source personal knowledge management system. In versions 3.6.3 and below, Mermaid diagrams are rendered with securityLevel set to \"loose\", and the resulting SVG is injected into the DOM via innerHTML. This allows attacker-controlled javascript: URLs in Mermaid code blocks to survive into the rendered output. On desktop builds using Electron, windows are created with nodeIntegration enabled and contextIsolation disabled, escalating the stored XSS to arbitrary code execution when a victim opens a note containing a malicious Mermaid block and clicks the rendered diagram node. This issue has been fixed in version 3.6.4."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 9.1,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-79",
              "description": "CWE-79: Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-94",
              "description": "CWE-94: Improper Control of Generation of Code (\u0027Code Injection\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-16T23:00:07.719Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-x63q-3rcj-hhp5",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-x63q-3rcj-hhp5"
        },
        {
          "name": "https://github.com/siyuan-note/siyuan/releases/tag/v3.6.4",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/siyuan-note/siyuan/releases/tag/v3.6.4"
        }
      ],
      "source": {
        "advisory": "GHSA-x63q-3rcj-hhp5",
        "discovery": "UNKNOWN"
      },
      "title": "SiYuan: Mermaid `javascript:` Link Injection Leads to Stored XSS and Electron RCE"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-40322",
    "datePublished": "2026-04-16T23:00:07.719Z",
    "dateReserved": "2026-04-10T21:41:54.505Z",
    "dateUpdated": "2026-04-16T23:00:07.719Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-40322\",\"sourceIdentifier\":\"security-advisories@github.com\",\"published\":\"2026-04-16T23:16:33.733\",\"lastModified\":\"2026-04-16T23:16:33.733\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"SiYuan is an open-source personal knowledge management system. In versions 3.6.3 and below, Mermaid diagrams are rendered with securityLevel set to \\\"loose\\\", and the resulting SVG is injected into the DOM via innerHTML. This allows attacker-controlled javascript: URLs in Mermaid code blocks to survive into the rendered output. On desktop builds using Electron, windows are created with nodeIntegration enabled and contextIsolation disabled, escalating the stored XSS to arbitrary code execution when a victim opens a note containing a malicious Mermaid block and clicks the rendered diagram node. This issue has been fixed in version 3.6.4.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H\",\"baseScore\":9.0,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"REQUIRED\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":2.3,\"impactScore\":6.0}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-79\"},{\"lang\":\"en\",\"value\":\"CWE-94\"}]}],\"references\":[{\"url\":\"https://github.com/siyuan-note/siyuan/releases/tag/v3.6.4\",\"source\":\"security-advisories@github.com\"},{\"url\":\"https://github.com/siyuan-note/siyuan/security/advisories/GHSA-x63q-3rcj-hhp5\",\"source\":\"security-advisories@github.com\"}]}}"
  }
}


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