SiYuan: Absolute filesystem path and OS username disclosure via resolveAssetPath

CVE: This vulnerability corresponds to CVE-2026-72802.

Summary

POST /api/asset/resolveAssetPath returns the resolved absolute filesystem path of an asset, unmodified. The route is CheckAuth-only, so it is reachable by the publish RoleReader token and by the anonymous account when Publish.Auth.Enable is false. An anonymous reader who knows any asset's relative path trivially harvested from an <img src="assets/…"> in any published document receives the server's absolute workspace path, disclosing the operating-system username and the installation layout.

Details

// kernel/api/asset.go: resolveAssetPath
p, err := model.GetAssetAbsPathInBox(path, "")   // boxID="" → absolute workspace path
...
ret.Data = p                                     // returned raw, no stripping

GetAssetAbsPathInBox(path, "") resolves under util.DataDir / util.WorkspaceDir, producing a full host path such as C:\Users\<username>\SiYuan\data\assets\foo.png or /home/<user>/…. The handler returns it directly with no redaction and no publish-scope check.

This is data the project already treats as sensitive. getConf explicitly zeroes System.WorkspaceDir, AppDir, ConfDir, DataDir, and HomeDir when util.IsBrowserRequest(c), a change made specifically to avoid leaking the username (issue #17410). resolveAssetPath performs no equivalent stripping, so it re-exposes precisely the values getConf was patched to hide.

Related unfiltered siblings in the same file, also CheckAuth-only with no publish scoping:

• getMissingAssets: workspace-wide list of missing asset references
• getUnusedAssets: every unused asset filename in the assets directory

Both return asset inventory spanning all documents, including publish-forbidden ones.

Verified at origin/master: resolveAssetPath returns the absolute path with no redaction, getConf contains the IsBrowserRequest stripping; 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.

1. Harvest an asset path: open any published document and read a relative asset path from its markup, e.g. assets/foo-20260101120000-abcdefg.png.

2. Resolve it as an anonymous reader:

POST http://127.0.0.1:6808/api/asset/resolveAssetPath
{"path":"assets/foo-20260101120000-abcdefg.png"}

3. Result: the response returns the absolute host path, e.g. C:\Users\<username>\SiYuan\data\assets\foo-...png disclosing the OS username and the full workspace/installation layout.

Control: getConf from the same anonymous session returns WorkspaceDir/DataDir/HomeDir blanked, confirming the project intends these values to be withheld from browser requests.

Related:

POST http://127.0.0.1:6808/api/asset/getUnusedAssets   {}
POST http://127.0.0.1:6808/api/asset/getMissingAssets  {}

Return workspace-wide asset inventory with no publish scoping.

Impact

An anonymous reader (publish mode with auth disabled) or any publish RoleReader obtains the server's absolute workspace path, which typically embeds the OS username, plus the installation directory layout. This is useful for targeting subsequent attacks (path construction, user enumeration, social engineering) and directly contradicts the redaction the project applies in getConf. The related endpoints additionally disclose workspace-wide asset inventory, including assets referenced only by publish-forbidden documents. Confidentiality-only.

Suggested fix

Apply the same redaction getConf uses: for browser/reader requests, return the asset path relative to the workspace root rather than the absolute host path (or omit it entirely). Add publish-access scoping to getUnusedAssets and getMissingAssets so their results are limited to documents the caller may see.