This vulnerability exposes a systematic authorization gap in SiYuan's block attribute retrieval endpoints. The core issue is that getBlockAttrs and batchGetBlockAttrs were treated as metadata plumbing rather than data access points, inheriting trust from the document rendering pipeline instead of enforcing their own publish-access checks. The fix in v3.7.4 corrected this for these specific endpoints, but the pattern is the real concern — these auxiliary endpoints exist to reduce client-side complexity (batch operations, preview generation, metadata retrieval) and almost always assume authorization is inherited rather than explicitly enforced. The data at risk is particularly sensitive: block names, aliases, memos, and custom fields encode organizational context — 'this block relates to Project Phoenix,' 'this person is a key stakeholder,' 'internal only.' An attacker who enumerates these attributes across many documents reconstructs not just what information exists, but how the organization categorizes and values that information. That's a knowledge graph, not a data leak. The CVSS 5.8 captures the technical access pattern but fundamentally misrepresents the intelligence value. A medium-rated CVE that reveals organizational knowledge hierarchy is more valuable to an attacker than a high-rated CVE exposing a single document body. The version history (fixed in v3.7.4) tells you when the gap was closed, not when it was introduced — it may have existed from initial feature scope, been stripped during refactoring, or never merged from a parallel branch. Regardless of origin, treat this as evidence that other attribute-adjacent endpoints in SiYuan's API may lack publish-access enforcement. Audit your block-level metadata endpoints for similar gaps, not just the ones explicitly patched. Organizations using SiYuan for sensitive knowledge management should treat this as a signal that their publish-access model may have structural blind spots at the metadata layer.
CVE-2026-72803
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedSiYuan versions before v3.7.4 fail to enforce publish-access checks in the getBlockAttrs and batchGetBlockAttrs endpoints. Attackers can retrieve block attributes including names, aliases, memos, and custom fields from protected documents by sending POST requests with block IDs.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysisThe application checks who you are but not whether you're allowed to perform a given action, so any authenticated user can reach things meant for others. This is the classic “change the ID in the URL” bug. The fix is an authorization check on every request, evaluated against the acting user's permissions.
General guidance for the missing authorization class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedv3.7.4
- Upgrade SiYuan to version v3.7.4 or later to resolve the missing authorization vulnerability in getBlockAttrs and batchGetBlockAttrs endpoints
Generated from the published advisory — verify against the referenced sources before acting.
There is no version to upgrade to and no patch to apply. Every affected install stays exposed until the vendor ships a fix — or somebody else builds one.
Free. We build fixes in the order the community asks for them — and we’ll tell you the moment this one lands.
We develop and verify an original fix where the vendor hasn’t, from $4,000. Deployed to your staging first — never straight to production.
Scope it with usSee what else the community needs solved on the solutions-needed board.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-72803 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesThis vulnerability exposes a systematic authorization gap in SiYuan's block attribute retrieval endpoints. The core issue is that getBlockAttrs and batchGetBlockAttrs were treated as metadata plumbing rather than data access points, inheriting trust from the document rendering pipeline instead of enforcing their own publish-access checks. The fix in v3.7.4 corrected this for these specific endpoints, but the pattern is the real concern — these auxiliary endpoints exist to reduce client-side complexity (batch operations, preview generation, metadata retrieval) and almost always assume authorization is inherited rather than explicitly enforced. The data at risk is particularly sensitive: block names, aliases, memos, and custom fields encode organizational context — 'this block relates to Project Phoenix,' 'this person is a key stakeholder,' 'internal only.' An attacker who enumerates these attributes across many documents reconstructs not just what information exists, but how the organization categorizes and values that information. That's a knowledge graph, not a data leak. The CVSS 5.8 captures the technical access pattern but fundamentally misrepresents the intelligence value. A medium-rated CVE that reveals organizational knowledge hierarchy is more valuable to an attacker than a high-rated CVE exposing a single document body. The version history (fixed in v3.7.4) tells you when the gap was closed, not when it was introduced — it may have existed from initial feature scope, been stripped during refactoring, or never merged from a parallel branch. Regardless of origin, treat this as evidence that other attribute-adjacent endpoints in SiYuan's API may lack publish-access enforcement. Audit your block-level metadata endpoints for similar gaps, not just the ones explicitly patched. Organizations using SiYuan for sensitive knowledge management should treat this as a signal that their publish-access model may have structural blind spots at the metadata layer.
Practitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-72803 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data