What’s Vulnerable › Vulnerabilities

CVE-2026-74903: SiYuan before v3.7.4 Insufficient Access Control via spinBlockDOM

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-18 · updated 2026-10-22
• Weakness: CWE-400

Description

SiYuan before v3.7.4 contains an insufficient access control vulnerability in the /api/lute/spinBlockDOM endpoint, which is guarded only by CheckAuth middleware instead of CheckAdminRole like its sibling endpoint. Authenticated users with RoleEditor or RoleReader roles can invoke the endpoint to transform arbitrary DOM input, and large payloads cause endpoint starvation through per-path mutex serialization.

Affected products

• siyuan-note siyuan: before 3.7.4 — fixed in 3.7.4

How to fix

Upgrade to a fixed version: siyuan-note siyuan 3.7.4. Check the vendor advisory for mitigations.

References

• https://github.com/siyuan-note/siyuan/security/advisories/GHSA-3j8q-5c8c-grwm
• https://www.vulncheck.com/advisories/siyuan-before-insufficient-access-control-via-spinblockdom
• https://github.com/siyuan-note/siyuan/security/advisories/GHSA-3j8q-5c8c-grwm

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