GHSA-gw25-m53r-qh88

## Summary SiYuan's `/export/` file handler was hardened against export disclosure (issue #12213) by adding an `IsSubPath(exportBaseDir, fullPath)` check and an `IsSensitivePath()` check in commit `bb481e1`. These guards were added only to the main branch of the handler. The handler begins with a short-circuit branch: ```go if strings.HasPrefix(c.Request.URL.Path, "/export/temp/") { c.File(filepath.Join(util.TempDir, c.Request.URL.Path)) return } ``` This branch joins the **broader** `util.TempDir` with the raw, percent-decoded request path and serves it with **neither** `IsSubPath` **nor** `IsSensitivePath`. An authenticated request to `/export/temp/%2e%2e/.../etc/passwd` traverses out of `TempDir` and reads arbitrary files - exactly the sensitive-file disclosure the patch intended to prevent. Present in the latest master. ## Affected - From commit `bb481e1` (the hardening) through the latest master. - Requires SiYuan access authorization (`model.CheckAuth`) - but the patch's stated goal is to deny sensitive-file export even to authorized callers. ## Root cause `kernel/server/serve.go` `serveExport()`: the main branch has `IsSubPath` + `IsSensitivePath`; the `/export/temp/` short-circuit branch (above it) has neither and uses `util.TempDir` as its root. `c.Request.URL.Path` is percent-decoded by net/http, so `%2e%2e` becomes `..` and `filepath.Join` collapses it. ## Incomplete-fix lineage - Export disclosure (issue #12213; CVE-2026-30869) -> fix `bb481e1` / `d68bd5a` (GHSA-6865-qjcf-286f): guards on the main branch + `IsSensitivePath` extended to `*.db`/`*.log`. - Follow-up CVE-2026-41894 (GHSA-hjh7-r5w8-5872) in the same `/export` path family. - The `/export/temp/` short-circuit branch was never covered by the guards (this report). ## Proof of concept (benign) 1. Authenticate (access auth code). 2. `GET /export/<sensitive>` (main branch) -> 401/403 (guards work). 3. `GET /export/temp/%2e%2e/%2e%2e/.../tmp/<planted-marker>` (or `/etc/hostname`) -> 2