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6.2 KiB
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6.2 KiB
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{"schema_version":"1.9.0","id":"GHSA-p4m3-mgmm-c664","published":"2026-07-10T19:25:04Z","modified":"2026-07-21T19:19:05.958413892Z","aliases":["CVE-2026-54066","GO-2026-5964"],"summary":"SiYuan: Path Traversal via Double URL Encoding in /assets/*path (publish mode arbitrary file─read), Incomplete fix of CVE-2026-41894 ","details":"## Summary\n The patch for CVE-2026-41894 (\"Path Traversal via Double URL Encoding\") sanitized the `/export/` route but the\n **identical root cause remains in the `/assets/*path` route**. In publish mode (anonymous read-only HTTP endpoint,\n default port 6808), an unauthenticated remote attacker can read arbitrary files inside `WorkspaceDir` — including\n `conf/conf.json` (which contains the `AccessAuthCode` SHA256 hash, API token, and sync keys), `temp/siyuan.db`,\n `temp/blocktree.db`, and `siyuan.log` — by double-URL-encoding `..` segments.\n\n Verified against siyuan v3.6.5:\n - `GET /assets/%252e%252e/%252e%252e/conf/conf.json` → **HTTP 200, 10349 bytes (conf.json served)**\n - `GET /export/%252e%252e/%252e%252e/conf/conf.json` → HTTP 401 (patched)\n - `GET /assets/%2e%2e/conf/conf.json` → HTTP 404 (single-decode handled correctly)\n\n ## Vulnerable Code\n\n **Step 1 — route & first decode** (`kernel/server/serve.go:587-626`):\n The router registers `GET /assets/*path` for the publish listener. Gin performs one URL decoding pass on `URL.Path`,\n so a request for `/assets/%252e%252e/...` yields `context.Param(\"path\") == \"/%2e%2e/%2e%2e/conf/conf.json\"` — literal\n `%2e%2e` strings, which `path.Clean` cannot collapse.\n\n **Step 2 — second decode via fallback** (`kernel/model/assets.go:536-563`, `GetAssetAbsPath`):\n ```go\n p, err := getAssetAbsPath(relativePath)\n if nil != err {\n // fallback\n decoded, e := url.PathUnescape(relativePath) // ← line 548, second decode\n if nil == e {\n p, err = getAssetAbsPath(decoded)\n }\n }\n ```\n After the fallback decodes `%2e%2e` to `..`, `filepath.Join(DataDir, \"../../conf/conf.json\")` is `Clean`-ed to\n `WorkspaceDir/conf/conf.json`, an existing file.\n\n **Step 3 — publish-mode access gate fall-through** (`kernel/model/publish_access.go:288`,\n `CheckAbsPathAccessableByPublishAccess`):\n ```go\n if !filelock.IsSubPath(util.DataDir, absPath) {\n return true // ← fall-through allows anything outside DataDir but inside WorkspaceDir\n }\n ```\n Because the resolved file is *outside* `DataDir` (it's in `WorkspaceDir`), the gate returns `true` and\n `IsSensitivePath()` is never invoked — `.db` / `.log` / `conf/` denylists do not apply to the `/assets/` route at all\n (unlike the patched `/export/` route, which additionally checks `IsSubPath(exportBaseDir, ...)`).\n\n **Step 4 — file served** (`http.ServeFile`): the request `URL.Path` contains literal `%2e%2e`, not `..`, so Go's\n `containsDotDot` guard passes and the file is sent.\n\n ## PoC\n\n Preconditions: siyuan kernel running with publish mode enabled (`conf.publish.enable = true`). Publish mode is the\n documented anonymous read-only endpoint for sharing notebooks.\n\n ```\n $ curl -i \"http://victim:6808/assets/%252e%252e/%252e%252e/conf/conf.json\"\n HTTP/1.1 200 OK\n Content-Length: 10349\n Content-Type: application/json\n ...\n {\"appearance\":{...},\"editor\":{...},\"system\":{...},\"accessAuthCode\":\"<sha256>\",\"api\":{\"token\":\"<api token>\"}, ...}\n ```\n\n Compared with the patched route:\n ```\n $ curl -i \"http://victim:6808/export/%252e%252e/%252e%252e/conf/conf.json\"\n HTTP/1.1 401 Unauthorized\n ```\n\n ## Root Cause\n Three independent flaws combine:\n 1. `GetAssetAbsPath` performs a second `url.PathUnescape` as a \"compatibility\" fallback, re-introducing the\n double-decode primitive that the CVE-2026-41894 patch eliminated on `/export/`.\n 2. `CheckAbsPathAccessableByPublishAccess` returns `true` for any path outside `DataDir`, even when that path is still\n inside `WorkspaceDir` (which contains `conf/conf.json`, `temp/*.db`, `siyuan.log`).\n 3. The `IsSensitivePath()` denylist applied to `/export/` is not called from the `/assets/` handler.\n\n ## Impact\n Unauthenticated remote arbitrary file read inside `WorkspaceDir`. Confirmed-readable files include:\n - `conf/conf.json` — `accessAuthCode` SHA256 (offline crackable), API token, S3/WebDAV sync credentials.\n - `temp/siyuan.db`, `temp/blocktree.db`, `temp/asset_content.db` — full notebook content (SQLite).\n - `siyuan.log` — internal paths, OS username, plugin info.\n\n Compromise of `accessAuthCode` / API token escalates to authenticated kernel API access (full read/write of all\n notebooks). Compromise of sync credentials escalates beyond the host.\n\n ## Fix\n 1. Remove the `url.PathUnescape` fallback in `GetAssetAbsPath` (assets.go:548), matching the `/export/` patch.\n 2. In `CheckAbsPathAccessableByPublishAccess`, replace the `IsSubPath(DataDir, ...)` fall-through with an explicit\n allowlist (only `DataDir` and its publishable subtree) and **always** call `IsSensitivePath()`.\n 3. Apply `IsSensitivePath()` inside the `/assets/*path` handler in `serve.go` as defense-in-depth.\n\n ## Status\n Privately reported via GitHub Security Advisory. PoC reproduced locally against v3.6.5 (publish port 6808): `GET\n /assets/%252e%252e/%252e%252e/conf/conf.json` returned HTTP 200 / 10349 bytes.","affected":[{"package":{"name":"github.com/siyuan-note/siyuan/kernel","ecosystem":"Go","purl":"pkg:golang/github.com/siyuan-note/siyuan/kernel"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.0.0-20260628153353-2d5d72223df4"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-p4m3-mgmm-c664/GHSA-p4m3-mgmm-c664.json"}}],"references":[{"type":"WEB","url":"https://github.com/siyuan-note/siyuan/security/advisories/GHSA-p4m3-mgmm-c664"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54066"},{"type":"PACKAGE","url":"https://github.com/siyuan-note/siyuan"}],"database_specific":{"cwe_ids":["CWE-1188","CWE-22","CWE-23"],"github_reviewed":true,"github_reviewed_at":"2026-07-10T19:25:04Z","nvd_published_at":"2026-06-24T22:16:48Z","severity":"HIGH"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"}]} |