Private block disclosure via missing publish checks
Published Aug 18, 2026 · Updated Aug 18, 2026
Missing authorization in SiYuan before 3.7.4 allows remote attackers to read private block text and metadata via block API calls. Seventeen handlers in kernel/api/block.go, including getRefText, getBlockBreadcrumb, and checkBlockExist, accept attacker-supplied block IDs after model.CheckAuth but never apply publish-access checks such as IsReadOnlyRoleContext or checkBlockPublishAccess before returning reference text, breadcrumbs, counts, tree data, and existence results. Exposure requires a published workspace because anonymous publish-mode readers can reach these endpoints; the flaw is read-only but lets outsiders probe arbitrary block IDs across the workspace and confirm or extract information from unpublished content.
Summary
What happened
Missing authorization in SiYuan before 3.7.4 allows remote attackers to read private block text and metadata via block API calls. Seventeen handlers in kernel/api/block.go, including getRefText, getBlockBreadcrumb, and checkBlockExist, accept attacker-supplied block IDs after model.CheckAuth but never apply publish-access checks such as IsReadOnlyRoleContext or checkBlockPublishAccess before returning reference text, breadcrumbs, counts, tree data, and existence results. Exposure requires a published workspace because anonymous publish-mode readers can reach these endpoints; the flaw is read-only but lets outsiders probe arbitrary block IDs across the workspace and confirm or extract information from unpublished content.
The record
- CVE
- CVE-2026-74904
- Published
- Aug 18, 2026
- Updated
- Aug 18, 2026
- Vendor
- SiYuan Note
- Product
- SiYuan
- Classifications
- CWE-862, T1213
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 18, 2026CVE publishedPublication date reported by the CVE source.
- Aug 18, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <3.7.4
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- GHSA-4vpg-gwqq-w44c step-by-step reproductionproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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