CVE-2026-69086: SiYuan: path traversal leaks attribute-view data

**CVE:** This vulnerability corresponds to [CVE-2026-69086](https://nvd.nist.gov/vuln/detail/CVE-2026-69086). ### Summary Four attribute-view read endpoints build a filesystem path from a caller-controlled `id`/`avID` and read it without confining the result to the attribute-view storage directory (`DataDir/storage/av/`). On the load (file-exists) code path there is no boundary check, so an `avID` containing `../` segments escapes `storage/av/` and causes the kernel to read a `.json` file elsewhere in the workspace. The endpoints require only `CheckAuth`, which the publish service's `RoleReader` token satisfies; when `Publish.Auth.Enable` is `false` the publish proxy uses the anonymous account, making the surface reachable with no credentials. ### Details Affected endpoints (all gated by `CheckAuth` only, no `CheckAdminRole`): - `POST /api/av/renderAttributeView` &nbsp;→ `arg["id"]` - `POST /api/av/getAttributeViewKeysByID` → `arg["avID"]` - `POST /api/av/getAttributeViewKeys` &nbsp;→ `arg["id"]` - `POST /api/av/getCurrentAttrViewImages` → `arg["id"]` In `model.RenderAttributeView` (`model/attribute_view_render.go`), the only identifier guard `ast.IsNodeIDPattern(avID)` sits **inside** the `if !filelock.IsExist(existPath)` (create) branch: ```go existPath = GetAttributeViewDataPath(avID) // path built from avID, no check if !filelock.IsExist(existPath) { // NOT-EXIST / CREATE branch if !createIfNotExist { return // NotFound } if !ast.IsNodeIDPattern(avID) { // <-- ONLY id guard, create branch only return ErrInvalidID } // ... create ... } attrView, err = av.ParseAttributeView(avID) // LOAD runs unconditionally ``` When the traversal `avID` resolves to a file that already exists, the `!filelock.IsExist(...)` condition is `false`, the entire block (including the line with `ast.IsNodeIDPattern`) is skipped, and control falls straight through to `av.ParseAttributeView(avID)`. That function rebuilds the path via `filepath.Join(DataDir, "storage", "av", avID+".json")` and calls `filelock.ReadFile` with no `filepath.Rel` / `IsSubPath` / `..` rejection: ```go // av.ParseAttributeView -> attributeViewDataPathByBox / GetAttributeViewDataPath avJSONPath = filepath.Join(DataDir, "storage", "av", avID+".json") // no boundary check // -> parseAttributeViewByPathInBox(avJSONPath, boxID) data, _ = filelock.ReadFile(avJSONPath) // SINK ``` `filepath.Join` cleans the path but does **not** reject `..` segments, so it provides no containment. The three `getAttributeView*` endpoints call `ParseAttributeView` with no create branch at all, so they never even reach the `ast.IsNodeIDPattern` check same defect, same auth tier. The root cause is that identifier validation is placed on a single code branch rather than confining the load to the AV base directory, so the load path reads a caller-controlled location. ### PoC **Precondition:** publish mode enabled (default port `6808`); reachable by a `RoleReader` publish token, or anonymously when `Publish.Auth.Enable` is `false`. A request to `/api/av/renderAttributeView` with an `id` composed of `../` path segments that resolves to an existing `.json` file outside `DataDir/storage/av/` causes that file to be read and parsed instead of being rejected, because the identifier validation is only reached on the not-exist/create branch. I have withheld the exact encoded `id` value from this draft to avoid publishing a live traversal against internet-exposed publish instances. I'm happy to provide the precise value and a screenshot privately in this thread on request. ### Impact An authenticated publish `RoleReader` or an anonymous client when publish auth is disabled can cause the kernel to read `.json` files outside the attribute-view directory. Because the loaded file is unmarshalled into the attribute-view structure, the reliable primitives are: 1. Disclosure of attribute-view (database) content from other scopes/notebooks the reader is not authorized to see. 2. A `.json`-path existence oracle for arbitrary workspace locations. Files not conforming to the AV schema are read but reflect little content, and the `.json` suffix is force-appended, so this is **not** a general arbitrary-file read. No admin role, CSRF token, or write permission is required. ### Suggested fix Validate `avID` with `ast.IsNodeIDPattern` before path construction on **all** branches (move it ahead of `FindAttributeViewPath` / `GetAttributeViewDataPath`), or preferably, so every caller inherits it confine at the sink: in `attributeViewDataPathByBox` / `GetAttributeViewDataPath`, compute the joined path and reject it unless `filepath.Rel(avBaseDir, cleaned)` stays within `avBaseDir` (no leading `..`). Sink-side confinement also covers the three `getAttributeView*` endpoints that never reach the create-branch guard.

An attacker discovers an internet-exposed SiYuan publish instance on the default port 6808 — for example, a team using SiYuan's publish feature to share a curated knowledge base externally. If the operator left Publish.Auth.Enable at its default false, the attacker connects anonymously; otherwise they use any low-privilege RoleReader token issued for legitimate read access to one notebook. They send a POST to /api/av/renderAttributeView with an id value built from `../` segments that resolves to an existing .json file elsewhere in the workspace — for instance, an attribute-view file belonging to a different, non-public notebook. Because that file already exists, SiYuan's identifier-validation check (nested only inside the 'not-exist/create' branch) never runs, and the kernel reads and parses the file, returning its attribute-view content to the attacker even though they were never authorized to see that notebook or scope.