XSS in Siyuan-Note Siyuan
CVE-2026-86712
SiYuan before 3.8.2 trusts the attacker-writable text/siyuan clipboard MIME type and skips sanitization in the paste handler, allowing code execution in the Node-enabled desktop renderer. Attackers can craft malicious web pages that write to the clipboard, and when pasted into SiYuan, injected scripts execute with full Node.js access through the Electron main process.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.007 (53.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 53rd percentile — 53.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.007 · change: +0.003
Affected products
Weakness classification (CWE)
References
- github.com/siyuan-note/siyuan/security/advisories/GHSA-9rr9-pxr4-gcgc (vendor-advisory)
- github.com/siyuan-note/siyuan/commit/9ce660652de2ced26ec2d98a5a242cb0b8bb7273 (patch)
- github.com/siyuan-note/siyuan/releases/tag/v3.8.2 (release-notes)
- github.com/siyuan-note/siyuan/blob/v3.8.1/app/src/protyle/util/paste.ts (technical-description)
- github.com/siyuan-note/siyuan (product)
- www.vulncheck.com/advisories/siyuan-before-3.8.2-remote-code-execution-via-clip… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-86712?
- CVE-2026-86712 is a high-severity vulnerability in Siyuan-Note Siyuan, classified under Cross-site Scripting. CVSS score: 8.8/10. Published 2026-09-08.
- How severe is CVE-2026-86712?
- High severity. CVSS v3 base score is 8.8 out of 10.