CVE-2026-44670: SiYuan Affected by Stored XSS via Attribute View Name to Electron Renderer RCE

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• Not in CISA KEV, but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
• EPSS 0.6%, percentile 45: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 45% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Only applies if your dependency tree includes github.com/siyuan-note/siyuan/kernel (Go) <= 0.0.0-20260421031503-96dfe0bea474, fixed in 0.0.0-20260512140701-d7b77d945e0d. Check your lockfile, including transitive dependencies.

What it is

SiYuan is an open-source personal knowledge management system. Prior to 3.7.0, the kernel stores Attribute View (AV / database) names without any HTML escape, then a render template uses raw strings.ReplaceAll(tpl, "${avName}", nodeAvName) to embed the name in HTML before pushing to all clients via WebSocket. Three independent client paths (render.ts:120 → outerHTML, Title.ts:401 → innerHTML, transaction.ts:559 → innerHTML) consume the value without escaping. Because the main BrowserWindow runs nodeIntegration:true, contextIsolation:false, webSecurity:false (app/electron/main.js:407-411), HTML injection in the renderer becomes Node.js code execution. This vulnerability is fixed in 3.7.0.

From the GitHub advisory

Summary

The kernel stores Attribute View (AV / database) names without any HTML escape, then a render template uses raw strings.ReplaceAll(tpl, "${avName}", nodeAvName) to embed the name in HTML before pushing to all clients via WebSocket. Three independent client paths (render.ts:120 → outerHTML, Title.ts:401 → innerHTML, transaction.ts:559 → innerHTML) consume the value without escaping. Because the main BrowserWindow runs nodeIntegration:true, contextIsolation:false, webSecurity:false (app/electron/main.js:407-411), HTML injection in the renderer becomes Node.js code execution.

Payload is stored on disk under data/storage/av/ .json, replicates via every sync transport (S3 / WebDAV / cloud), survives .sy.zip export-import, and triggers for any role (Administrator / Editor / Reader / publish-service Visitor) opening a doc bound to the AV.

Details

Kernel write — no escape. kernel/model/attributeview.go:3244-3255:

Weakness type: CWE-79, CWE-94, CWE-1188.

Product: github.com/siyuan-note/siyuan/kernel (Go) · Assigned by: GitHub_M · Published: 2026-05-14

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Attack requirements: none
• Privileges required: none (no login)
• User interaction: passive

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation poc, automatable no, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.55% probability of exploitation activity in the next 30 days; percentile 45.

Timeline

• 2026-05-08 — GitHub-reviewed advisory GHSA-2h64-c999-c9r6 published (critical)
• 2026-05-14 — CVE record published by GitHub_M
• 2026-05-15 — CVE record last updated

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-2h64-c999-c9r6 github.com
2. CVE.org record CVE-2026-44670 cve.org
3. NVD entry CVE-2026-44670 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com

Critical Go advisories · Today’s Security Digest