SiYuan: Path Traversal via unvalidated avID in RenderAttributeView/AV read endpoints : reader-reachable cross-scope attribute-view disclosure
漏洞描述
**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` → `arg["id"]` - `POST /api/av/getAttributeViewKeysByID` → `arg["avID"]` - `POST /api/av/getAttributeViewKeys` → `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. Source Code Location: https://github.com/siyuan-note/siyuan Affected Packages: - go:github.com/siyuan-note/siyuan/kernel, affected < 0.0.0-20260720151813-0f5a0e7c67b0, patched in 0.0.0-20260720151813-0f5a0e7c67b0 CWEs: - CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') CVSS: - Primary: score 7.7, CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N - CVSS_V3: score 7.7, CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N References: - https://github.com/siyuan-note/siyuan/security/advisories/GHSA-7hm9-v7vf-7g4w - https://nvd.nist.gov/vuln/detail/CVE-2026-69086 - https://www.vulncheck.com/advisories/siyuan-before-path-traversal-via-unvalidated-avid - https://github.com/advisories/GHSA-7hm9-v7vf-7g4w