CVE-2026-66395 SiYuan Desktop before v3.7.2 Reflected XSS to RCE via siyuan Protocol
Attackers can execute arbitrary code with Node.js privileges by crafting malicious deep links that trigger reflected XSS in the plugin readme handler.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-66395?
CVE-2026-66395 is a critical cross-site scripting vulnerability in siyuan-note siyuan, published on 27 Jul 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
SiYuan desktop before v3.7.2 contains a reflected cross-site scripting vulnerability in the bazaar plugin readme handler that allows attackers to execute arbitrary code by crafting a malicious siyuan:// deep link. Attackers can inject HTML payloads via the plugin name parameter that execute with full Node.js access through insertAdjacentHTML rendering in an insecurely configured Electron renderer.
Weakness: CWE-79
Which versions are affected by CVE-2026-66395?
How do I fix CVE-2026-66395?
No fix has been published for CVE-2026-66395 yet. Limit exposure of the affected software until one is available.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2026-66395 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-66395 exists.
Sources
Also known as GHSA-6gx2-8gcr-x83f, GHSA-x52j-m89g-wh64.