« Back to list

CVE-2026-39846

Status: AnalyzedCritical (9)—

SiYuan is a personal knowledge management system. Prior to 3.6.4, a malicious note synced to another user can trigger remote code execution in the SiYuan Electron desktop client. The root cause is that table caption content is stored without safe escaping and later unescaped into rendered HTML, creating a stored XSS sink. Because the desktop renderer runs with nodeIntegration enabled and contextIsolation disabled, attacker-controlled JavaScript executes with access to Node.js APIs. In practice, an attacker can import a crafted note into a synced workspace, wait for the victim to sync, and achieve code execution when the victim opens the note. This vulnerability is fixed in 3.6.4.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

XSS almacenado en contenido de tabla (CWE-79) que ejecuta JavaScript en cliente Electron con nodeIntegration habilitado, permitiendo ejecución de código arbitrario tras sincronización de nota maliciosa.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Restrict Web-Based ContentUser TrainingPrivileged Account ManagementNetwork Intrusion PreventionLimit Software InstallationExecution Prevention

Affected technologies (1)

B3log — Siyuan

CWEs

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2026-39846",
  "cveTags": [],
  "metrics": {
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-39846",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-04-08T15:23:34.478628Z"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "security-advisories@github.com",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 9,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 6,
        "exploitabilityScore": 2.3
      },
      {
        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "CHANGED",
          "version": "3.1",
          "baseScore": 9,
          "attackVector": "NETWORK",
          "baseSeverity": "CRITICAL",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "REQUIRED",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 6,
        "exploitabilityScore": 2.3
      }
    ]
  },
  "affected": [
    {
      "source": "security-advisories@github.com",
      "affectedData": [
        {
          "vendor": "siyuan-note",
          "product": "siyuan",
          "versions": [
            {
              "status": "affected",
              "version": "< 3.6.4"
            }
          ]
        }
      ]
    }
  ],
  "published": "2026-04-07T22:16:23.597",
  "references": [
    {
      "url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-phhp-9rm9-6gr2",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "source": "security-advisories@github.com"
    },
    {
      "url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-phhp-9rm9-6gr2",
      "tags": [
        "Exploit",
        "Vendor Advisory"
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-advisories@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        },
        {
          "lang": "en",
          "value": "CWE-94"
        }
      ]
    },
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "SiYuan is a personal knowledge management system. Prior to 3.6.4, a malicious note synced to another user can trigger remote code execution in the SiYuan Electron desktop client. The root cause is that table caption content is stored without safe escaping and later unescaped into rendered HTML, creating a stored XSS sink. Because the desktop renderer runs with nodeIntegration enabled and contextIsolation disabled, attacker-controlled JavaScript executes with access to Node.js APIs. In practice, an attacker can import a crafted note into a synced workspace, wait for the victim to sync, and achieve code execution when the victim opens the note. This vulnerability is fixed in 3.6.4."
    },
    {
      "lang": "es",
      "value": "SiYuan es un sistema de gestión de conocimiento personal. Antes de la versión 3.6.4, una nota maliciosa sincronizada con otro usuario puede desencadenar la ejecución remota de código en el cliente de escritorio SiYuan Electron. La causa raíz es que el contenido de la leyenda de la tabla se almacena sin un escape seguro y luego se desescapa en HTML renderizado, creando un sumidero XSS almacenado. Debido a que el renderizador de escritorio se ejecuta con nodeIntegration habilitado y contextIsolation deshabilitado, el JavaScript controlado por el atacante se ejecuta con acceso a las API de Node.js. En la práctica, un atacante puede importar una nota manipulada en un espacio de trabajo sincronizado, esperar a que la víctima sincronice y lograr la ejecución de código cuando la víctima abre la nota. Esta vulnerabilidad está corregida en la versión 3.6.4."
    }
  ],
  "lastModified": "2026-07-20T20:10:00.110",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "3951F8B9-C26F-4A2E-98FB-F744EB1F67B8",
              "versionEndExcluding": "3.6.4"
            }
          ],
          "operator": "OR"
        }
      ]
    }
  ],
  "sourceIdentifier": "security-advisories@github.com"
}