CVE-2026-72800: SiYuan: broken authz leaks DB schema & block IDs

**CVE:** This vulnerability corresponds to [CVE-2026-72800](https://nvd.nist.gov/vuln/detail/CVE-2026-72800). ### Summary `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): ```go 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 `avID`s 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 ``` ### 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. ### 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. ### Suggested fix - 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.

An attacker browses a public SiYuan publish-mode site (or, if `Publish.Auth.Enable` is false, accesses it anonymously) and opens any published document that embeds a database view. From the page's HTML they extract the `data-av-id` attribute value for that database. They then send `POST /api/av/getAttributeViewKeysByID` with that avID and an empty `keyIDs` array, receiving the full column schema — including select-option vocabularies that may encode sensitive labels like 'Confidential' or 'Terminated' — for a database whose host document is actually hidden or password-protected. Noticing a `Relation` field pointing to another avID, the attacker repeats the call to pivot into a second, unrelated database's schema. Separately, they call `getBlockDefIDsByRefText` with common anchor text to harvest valid block IDs from private documents workspace-wide, then feed a returned ID into `getBlockRelevantIDs` to walk parent/sibling/child relationships — including inside an encrypted notebook that happens to be unlocked on the server — building a map of content structure that can be fed into other (already-authenticated) block-content endpoints to retrieve the actual private text.