Vulnerability · Published Aug 19, 2026 · Assigned by VulnCheck

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

High 8.6

In plain English

A high-severity cross-site scripting in siyuan from siyuan-note. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 13% of all known vulnerabilities).

Severity (CVSS 3.1)8.6High

Exploit odds (30 days)0.2%top 86.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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 (as reported)

Vendor	Product	Versions
siyuan-note	siyuan	see references

Weakness: CWE-79 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

References

GitHub Security Advisory (GHSA-5prr-vgxq-69g9) vendor-advisory
VulnCheck Advisory: SiYuan XSS-to-RCE via unescaped block metadata in hint popup third-party-advisory