CVE-2026-75916 SiYuan XSS-to-RCE via unescaped block metadata in hint popup
Attackers can execute arbitrary OS commands by injecting scripts into block metadata, exploiting XSS in the autocomplete popup of the SiYuan desktop application.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-75916?
CVE-2026-75916 is a critical cross-site scripting vulnerability in siyuan-note siyuan, published on 19 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
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.
Weakness: CWE-79
Which versions are affected by CVE-2026-75916?
How do I fix CVE-2026-75916?
No fix has been published for CVE-2026-75916 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-2026-75916 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-75916 exists.
Sources
Also known as GHSA-5prr-vgxq-69g9, GHSA-962c-hgx6-ffmx.