High CVSS 8.7
CVE-2026-66394
NVD analysis in progress
SiYuan before v3.7.3 contains stored and reflected cross-site scripting vulnerabilities in SVG sanitization that allows authenticated attackers to execute scripts by bypassing the HTML parser-based cleaner. Attackers can hide script tags within desc, style, or noscript elements which the HTML parser treats as raw text but browsers interpret as executable SVG content when served as image/svg+xml, enabling script execution in the application origin.
What this means
- Exposure
- Exploitable remotely over the network and with an ordinary user account — but only if a user opens booby-trapped content.
- Impact
- An attacker can read sensitive data and modify or destroy data. The impact spreads beyond the vulnerable component into other parts of the system.
- Weakness
- Attacker-supplied script runs in other users’ browsers (cross-site scripting).
- Likelihood
- Its EPSS score stays low: nothing points to imminent exploitation, which is no reason to leave it unpatched.
What to doFold into the next patch cycle.
Read automatically from the CVSS vector, the weakness type (CWE) and the EPSS score. The technical description above remains the one published by NIST.