What’s Vulnerable › Vulnerabilities

CVE-2026-93923: SiYuan through 3.8.4 Stored XSS via Heading Style Attribute

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-19 · updated 2026-09-21
• Weakness: CWE-79

Description

SiYuan through 3.8.4 fails to escape heading style attributes when rendering outline and bookmark dock HTML, allowing stored cross-site scripting. Attackers can supply crafted notebooks or call administrative endpoints to inject malicious style values that execute in the Electron renderer with full system access.

Affected products

• siyuan-note siyuan: through 3.8.4

References

• https://github.com/siyuan-note/siyuan
• https://github.com/siyuan-note/siyuan/blob/v3.8.4/app/src/util/Tree.ts#L133
• https://github.com/siyuan-note/siyuan/blob/v3.8.4/app/src/util/Tree.ts#L194
• https://github.com/siyuan-note/siyuan/blob/v3.8.4/kernel/model/render.go#L71-L76
• https://github.com/siyuan-note/siyuan/security/advisories/GHSA-928g-4hfq-qwvx
• https://www.vulncheck.com/advisories/siyuan-through-3.8.4-stored-xss-via-heading-style-attribute
• https://github.com/siyuan-note/siyuan/security/advisories/GHSA-928g-4hfq-qwvx

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