High severity · published Aug 18, 2026
CVE-2026-74904
SiYuan before v3.7.4 Missing Authorization via block API
7.5
CVSS
0.4%
EPSS
No
On KEV
Description
SiYuan before v3.7.4 is missing authorization checks in 17 block metadata/content endpoints in kernel/api/block.go (including getRefText, checkBlockExist, and getBlockBreadcrumb). These handlers are gated only by basic authentication (model.CheckAuth) and lack publish-access filtering, allowing anonymous publish-mode readers to disclose private block content-derived text, structural metadata, and existence information for arbitrary block IDs across the workspace.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 39% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SI
siyuan · siyuan-note
before 3.7.4 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-74904
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-74904
github.com
https://github.com/siyuan-note/siyuan/security/advisories/GHSA-4vpg-gwqq-w44c
www.vulncheck.com
https://www.vulncheck.com/advisories/siyuan-before-missing-authorization-via-block-api
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