CVE-2026-72800

CVE-2026-72800 is a medium-severity missing authorization vulnerability in github.com/siyuan-note/siyuan/kernel (go), affecting versions < 0.0.0-20260724103335-f36331956ae9. It is fixed in 0.0.0-20260724103335-f36331956ae9.

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Summary

SiYuan: Missing publish-access filter on getAttributeViewKeysByID discloses database column schema, plus two unscoped block-ID enumeration oracles (publish mode)

CVE: This vulnerability corresponds to CVE-2026-72800.

POST /api/av/getAttributeViewKeysByID returns a database's full column schema with no publish-access filtering, while its sibling getAttributeViewKeys applies the filter for reader sessions. Two further endpoints, getBlockDefIDsByRefText and getBlockRelevantIDs return workspace-wide block IDs with no publish scoping. All three are CheckAuth-only, so they are reachable by the publish RoleReader token and by the anonymous account when Publish.Auth.Enable is false.

Details

(a) getAttributeViewKeysByID: ungated column-schema disclosure

The entire handler (kernel/api/av.go, router line 548):

ret.Data = model.GetAttributeViewKeysByID(avID, keyIDs...)   // no publish gate

With an empty keyIDs, GetAttributeViewKeysByID calls av.ParseAttributeView(avID) and returns every column's *av.Key:

Field Discloses
Name, Desc column title and user-authored description
Options the full single/multi-select vocabulary and colours (e.g. status labels such as "Fired", "Confidential")
Template the column's Sprig template expression, logic and field references
Relation the target avID, allowing pivot to another database
Rollup, NumberFormat, date config further schema

Guarded-sibling asymmetry, same file: getAttributeViewKeys (router line 526) runs FilterBlockAttributeViewKeysByPublishAccess(...) when IsReadOnlyRoleContext. getAttributeViewKeysByID applies nothing. A reader who knows an avID, trivially harvested from the data-av-id attribute of any published document embedding a database obtains the schema of any database in the workspace, including those whose host documents are hidden, password-protected, or publish-forbidden. Relation targets allow walking to sibling databases.

(b) Two unscoped block-ID enumeration oracles

Both CheckAuth-only with no publish gate. Neither returns content of its own, but both yield valid block IDs that other endpoints turn into content:

  • getBlockDefIDsByRefText (router line 237) → GetBlockDefIDsByRefText(anchor) returns the block IDs, workspace-wide and including private documents, whose reference/anchor text equals a caller-supplied string: a ref-text → ID oracle.
  • getBlockRelevantIDs (router line 274) → GetBlockRelevantIDsInBox(id, <notebook from request>) returns parent/previous/next block IDs and traverses decrypted encrypted-notebook structure while the notebook is unlocked, a tree-walk oracle.

Verified at origin/master (eef105683): all three handler bodies contain no publish-access, publish-ignore, or readonly-role check; all three routes are registered CheckAuth without CheckAdminRole.

Proof of Concept

Precondition: publish mode enabled (default port 6808); anonymous when Publish.Auth.Enable is false, otherwise any publish reader account. A database exists whose host document is publish-forbidden or password-protected.

(a) Column schema of any database:

POST http://127.0.0.1:6808/api/av/getAttributeViewKeysByID
{"avID":"<AV_ID>"}

Returns every column's key object names, descriptions, select vocabularies, template expressions, and Relation target avIDs for a database whose host document the reader may not access.

Control: the sibling getAttributeViewKeys with the same avID returns filtered results for the same reader session, confirming the boundary is enforced there and omitted here.

(b) ID oracles:

POST http://127.0.0.1:6808/api/block/getBlockDefIDsByRefText
{"anchor":"<known ref text>"}
→ block IDs workspace-wide, including blocks in private documents

POST http://127.0.0.1:6808/api/block/getBlockRelevantIDs
{"id":"<BLOCK_ID>","notebook":"<BOX_ID>"}
→ parent/previous/next block IDs; traverses encrypted-notebook structure when unlocked

Note

getAttributeViewKeysByID is a distinct handler from getAttributeView; although column definitions also appear within the latter's response payload, a fix applied to one handler does not remediate the other, and getAttributeViewKeysByID has its own filtered sibling (getAttributeViewKeys) demonstrating the intended treatment.

Impact

An anonymous reader (publish mode with auth disabled) or any publish RoleReader can read the complete column schema of any database in the workspace, including column descriptions, select-option vocabularies (which frequently encode sensitive category labels), template logic, and relation targets that permit pivoting to further databases regardless of whether the host document is hidden, password-protected, or excluded from publishing.

The two enumeration endpoints additionally supply valid block IDs across the publish boundary, including from encrypted notebooks while unlocked. This removes the "attacker must already know a valid ID" precondition from other block-read endpoints, converting ID knowledge into content disclosure. Confidentiality-only.

The application does not perform an authorization check before performing a sensitive operation. Typical impact: unauthorized access to restricted functionality or data.

CVE-2026-72800 has a CVSS score of 5.8 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.0.0-20260724103335-f36331956ae9); upgrading removes the vulnerable code path.

Affected versions

github.com/siyuan-note/siyuan/kernel (< 0.0.0-20260724103335-f36331956ae9)

Security releases

github.com/siyuan-note/siyuan/kernel → 0.0.0-20260724103335-f36331956ae9 (go)

Kodem intelligence

Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.

Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.

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Remediation advice

  • Gate getAttributeViewKeysByID with FilterBlockAttributeViewKeysByPublishAccess, mirroring getAttributeViewKeys.
  • Scope getBlockDefIDsByRefText and getBlockRelevantIDs to publish-accessible blocks for reader sessions, and ensure the *InBox traversal path applies the same check before walking encrypted-notebook structure.

Frequently Asked Questions

  1. What is CVE-2026-72800? CVE-2026-72800 is a medium-severity missing authorization vulnerability in github.com/siyuan-note/siyuan/kernel (go), affecting versions < 0.0.0-20260724103335-f36331956ae9. It is fixed in 0.0.0-20260724103335-f36331956ae9. The application does not perform an authorization check before performing a sensitive operation.
  2. How severe is CVE-2026-72800? CVE-2026-72800 has a CVSS score of 5.8 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
  3. Which versions of github.com/siyuan-note/siyuan/kernel are affected by CVE-2026-72800? github.com/siyuan-note/siyuan/kernel (go) versions < 0.0.0-20260724103335-f36331956ae9 is affected.
  4. Is there a fix for CVE-2026-72800? Yes. CVE-2026-72800 is fixed in 0.0.0-20260724103335-f36331956ae9. Upgrade to this version or later.
  5. Is CVE-2026-72800 exploitable, and should I be worried? Whether CVE-2026-72800 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
  6. What actually determines whether CVE-2026-72800 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
  7. How do I fix CVE-2026-72800? Upgrade github.com/siyuan-note/siyuan/kernel to 0.0.0-20260724103335-f36331956ae9 or later.

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