CVE-2026-41894

The fix for CVE-2026-30869 in SiYuan v3.5.10 only added a denylist check (IsSensitivePath) but did not address the root cause, a redundant url.PathUnescape() call in serveExport(). An authenticated attacker can use double URL encoding (%252e%252e) to traverse directories and read arbitrary workspace files including the full SQLite database (siyuan.db), kernel log, and all user documents.

Details

In kernel/server/serve.go, the serveExport() function (line 314-320) processes file paths as follows:

filePath := strings.TrimPrefix(c.Request.URL.Path, "/export/")
decodedPath, err := url.PathUnescape(filePath)     // second decode
fullPath := filepath.Join(exportBaseDir, decodedPath)

Go's HTTP server already decodes percent-encoded characters once during request parsing. The additional url.PathUnescape() call creates a double-decode vulnerability:

1. Attacker sends: GET /export/%252e%252e/siyuan.db
2. Go HTTP decodes %25 → %, result: URL.Path = /export/%2e%2e/siyuan.db
3. Go's path cleaner sees %2e%2e as literal characters (not ..), no redirect occurs
4. url.PathUnescape("%2e%2e") decodes to ..
5. filepath.Join(exportBaseDir, "../siyuan.db") resolves to <workspace>/temp/siyuan.db

The CVE-2026-30869 fix added IsSensitivePath() which blocks <workspace>/conf/ and OS-level paths (/etc, /root, etc.). However, it does NOT block:

• <workspace>/temp/siyuan.db, full document database
• <workspace>/temp/blocktree.db, block tree database
• <workspace>/temp/siyuan.log, kernel log
• <workspace>/temp/asset_content.db, asset content database

Note: the /appearance/ handler in the same file correctly uses gulu.File.IsSubPath() to validate paths (line 447), but this check is missing from the /export/ handler.

PoC

poc.zip
Please extract the uploaded compressed file before proceeding

1. docker compose up -d --build
2. sh poc.sh

• Data exfiltration: An authenticated user (including low-privilege Publish/Reader users via the Publish service) can download the entire SQLite document database containing all blocks, documents, attributes, and full-text search indexes.
• Information disclosure: Kernel log (siyuan.log) leaks internal server paths, versions, configuration details, and error messages.

Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.

Kodem intelligence

1. What is CVE-2026-41894? CVE-2026-41894 is a high-severity path traversal vulnerability in github.com/siyuan-note/siyuan/kernel (go), affecting versions < 3.6.5. It is fixed in 3.6.5. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
2. Which versions of github.com/siyuan-note/siyuan/kernel are affected by CVE-2026-41894? github.com/siyuan-note/siyuan/kernel (go) versions < 3.6.5 is affected.
3. Is there a fix for CVE-2026-41894? Yes. CVE-2026-41894 is fixed in 3.6.5. Upgrade to this version or later.
4. Is CVE-2026-41894 exploitable, and should I be worried? Whether CVE-2026-41894 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
5. What actually determines whether CVE-2026-41894 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
6. How do I fix CVE-2026-41894? Upgrade github.com/siyuan-note/siyuan/kernel to 3.6.5 or later.