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High CVSS 8.4

CVE-2026-66396

NVD analysis in progress

SiYuan before v3.7.2 fails to escape the title-img Individual Attribute List value when rendering Gallery and Kanban cover images, allowing stored cross-site scripting via unescaped style attribute interpolation. Attackers with editor permissions can inject onload handlers that execute arbitrary code in the Electron renderer with full Node.js access when victims open affected documents.

What this means

Exposure
Exploitable remotely over the network and with a privileged account — but only if a user opens booby-trapped content.
Impact
An attacker can read sensitive data, modify or destroy data and take the service offline. 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.

Published
27 July 2026
CVSS
8.4 (v3.1) CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:H
EPSS
0.3% probability of exploitation within 30 days · above 22% of all CVEs
Weakness
CWE-79
Sources
nvd
References

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