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

Quick assessment

Affected
siyuan-note siyuan
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

SiYuan是SiYuan团队开源的一款文档管理软件。 SiYuan 3.7.4之前版本存在资源管理错误漏洞，该漏洞源于/api/lute/spinBlockDOM端点访问控制不当，仅由CheckAuth中间件保护，缺少CheckAdminRole权限校验，已认证用户可调用该端点转换任意DOM输入，大型负载通过路径互斥序列化导致端点资源耗尽。

CVSS 4.3 · Medium EPSS 0.21% · P11

Possible ATT&CK Techniques 1 AI

T1135 · Network Share Discovery

Affected Version Matrix 2

VendorProduct Version RangeStatus
siyuan-note siyuan < 3.7.4 affected
3.7.4 unaffected
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I. Basic Information for CVE-2026-74903

Vulnerability Information
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Vulnerability Title
SiYuan before v3.7.4 Insufficient Access Control via spinBlockDOM
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
未加控制的资源消耗(资源穷尽)
Source: CVE Program / CVE List V5
Vulnerability Title
SiYuan 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
SiYuan是SiYuan团队开源的一款文档管理软件。 SiYuan 3.7.4之前版本存在资源管理错误漏洞，该漏洞源于/api/lute/spinBlockDOM端点访问控制不当，仅由CheckAuth中间件保护，缺少CheckAdminRole权限校验，已认证用户可调用该端点转换任意DOM输入，大型负载通过路径互斥序列化导致端点资源耗尽。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
siyuan-note siyuan 0 ~ 3.7.4 -

II. Public POCs for CVE-2026-74903

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III. Intelligence Information for CVE-2026-74903

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Vendor Advisories for CVE-2026-74903 (2)

Same Patch Batch · siyuan-note · 2026-08-18 · 5 CVEs total

CVE-2026-74902 8.6 HIGH SiYuan before v3.7.4 XSS-to-RCE via malicious filename upload
CVE-2026-74906 7.5 HIGH SiYuan before v3.7.4 Incorrect Authorization via Publish Access
CVE-2026-74904 7.5 HIGH SiYuan before v3.7.4 Missing Authorization via block API
CVE-2026-74905 7.1 HIGH SiYuan before v3.7.4 SSRF via IPv6 Transition Address Bypass

IV. Related Vulnerabilities

Same product: siyuan
Same vendor: siyuan-note
Same weakness: CWE-400

V. Comments for CVE-2026-74903

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