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PatchSiren cyber security CVE debrief

CVE-2026-56395 SiYuan CVE debrief

CVE-2026-56395 is a critical vulnerability in SiYuan before v3.6.1. The issue allows malicious package authors to inject arbitrary HTML and JavaScript into package metadata and README content in the Bazaar marketplace. This enables attackers to achieve remote code execution on any user browsing the Bazaar by embedding XSS payloads in package displayName, description, or README fields. The vulnerability exploits Electron's nodeIntegration setting to execute OS commands. Defenders should prioritize patching to limit exposure.

Vendor
SiYuan
Product
Unknown
CVSS
CRITICAL 9.4
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-21
Original CVE updated
2026-09-17
Advisory published
2026-06-21
Advisory updated
2026-09-17

Who should care

Users of SiYuan before v3.6.1, particularly those who utilize the Bazaar marketplace, should prioritize updating to the latest version to mitigate the risk of remote code execution. Developers and administrators who manage SiYuan installations are also advised to take immediate action.

Technical summary

The vulnerability, CVE-2026-56395, is caused by inadequate sanitization of package metadata and README content in the Bazaar marketplace of SiYuan before v3.6.1. Malicious package authors can inject arbitrary HTML and JavaScript, leading to remote code execution when users view the Bazaar. The attack leverages Electron's nodeIntegration setting to execute OS commands. The CVSS score is 9.4, indicating a critical severity.

Defensive priority

Immediate patching recommended due to critical severity and potential for remote code execution

Recommended defensive actions

  • Update SiYuan to version 3.6.1 or later
  • Review and sanitize package metadata and README content in the Bazaar marketplace
  • Limit user access to the Bazaar marketplace until patched
  • Monitor for suspicious activity in SiYuan installations
  • Implement additional security measures to restrict execution of OS commands

Evidence notes

The primary evidence for this vulnerability comes from the CVE record and NVD detail. The CVE-2026-56395 record indicates that SiYuan before v3.6.1 is affected. The NVD detail provides additional information on the vulnerability's CVSS vector and weaknesses. Defenders should verify the affected product and version from official sources.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-56395 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-56395

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-56395 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-56395

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.