What’s Vulnerable › Vulnerabilities

CVE-2026-75916: SiYuan XSS-to-RCE via unescaped block metadata in hint popup

• Severity: high (CVSS 8.6 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-19 · updated 2026-10-08
• Weakness: CWE-79

Description

SiYuan through 3.7.3 contains a cross-site scripting vulnerability in the '((' block-reference autocomplete hint popup. In genHintItemHTML() (app/src/protyle/hint/extend.ts), a candidate block's name, alias, and memo fields are concatenated into the popup's HTML without escaping. An attacker who can set these metadata fields on a block can inject a self-firing payload (e.g. <img src=x onerror=...>) that executes automatically when a victim types '((' followed by a search term that surfaces the crafted block. Because SiYuan's Electron windows run with nodeIntegration enabled, contextIsolation disabled, and no CSP, the injected script gains require('child_process') access, allowing the XSS to escalate to arbitrary OS command execution.

Affected products

• siyuan-note siyuan: all versions

References

• https://github.com/siyuan-note/siyuan/security/advisories/GHSA-5prr-vgxq-69g9
• https://www.vulncheck.com/advisories/siyuan-xss-to-rce-via-unescaped-block-metadata-in-hint-popup
• https://github.com/siyuan-note/siyuan/security/advisories/GHSA-5prr-vgxq-69g9

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