GHSA-GW25-M53R-QH88

Vulnerability from github – Published: 2026-09-03 14:56 – Updated: 2026-09-03 14:56
VLAI
Summary
SiYuan: path traversal via /export/temp/ short-circuit branch (incomplete fix for the export-disclosure hardening, GHSA-6865-qjcf-286f)
Details

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:

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) -> 200 + file content, demonstrating the unguarded traversal. The PoC reads only a planted marker / /etc/hostname; no credentials.

Impact

Authenticated arbitrary file read bypassing the sensitive-file protection: /etc/passwd, ~/.ssh/*, SiYuan *.db workspace data, *.log.

Remediation

  • Apply IsSubPath + IsSensitivePath to the /export/temp/ branch (or restrict its root to TempDir/temp with an IsSubPath check).
  • filepath.Clean the request path and reject ...
  • Merge both branches into one guarded file-serving function.

References

  • Hardening advisory: https://github.com/siyuan-note/siyuan/security/advisories/GHSA-6865-qjcf-286f (commit d68bd5a); issue #12213.
  • CVE chain: CVE-2026-30869 -> CVE-2026-41894 (GHSA-hjh7-r5w8-5872).
  • serve.go guards commit: https://github.com/siyuan-note/siyuan/commit/bb481e1290c4a34255652ede85a546504505d2a7
  • Residual source (master): kernel/server/serve.go serveExport() lines 308-312.
Show details on source website

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/siyuan-note/siyuan/kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.0.0-20260510110132-b763d787d1f2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-03T14:56:31Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "## Summary\nSiYuan\u0027s `/export/` file handler was hardened against export disclosure (issue #12213) by adding an\n`IsSubPath(exportBaseDir, fullPath)` check and an `IsSensitivePath()` check in commit `bb481e1`. These guards\nwere added only to the main branch of the handler. The handler begins with a short-circuit branch:\n```go\nif strings.HasPrefix(c.Request.URL.Path, \"/export/temp/\") {\n    c.File(filepath.Join(util.TempDir, c.Request.URL.Path))\n    return\n}\n```\nThis branch joins the **broader** `util.TempDir` with the raw, percent-decoded request path and serves it with\n**neither** `IsSubPath` **nor** `IsSensitivePath`. An authenticated request to\n`/export/temp/%2e%2e/.../etc/passwd` traverses out of `TempDir` and reads arbitrary files - exactly the\nsensitive-file disclosure the patch intended to prevent. Present in the latest master.\n\n## Affected\n- From commit `bb481e1` (the hardening) through the latest master.\n- Requires SiYuan access authorization (`model.CheckAuth`) - but the patch\u0027s stated goal is to deny sensitive-file\n  export even to authorized callers.\n\n## Root cause\n`kernel/server/serve.go` `serveExport()`: the main branch has `IsSubPath` + `IsSensitivePath`; the\n`/export/temp/` short-circuit branch (above it) has neither and uses `util.TempDir` as its root.\n`c.Request.URL.Path` is percent-decoded by net/http, so `%2e%2e` becomes `..` and `filepath.Join` collapses it.\n\n## Incomplete-fix lineage\n- Export disclosure (issue #12213; CVE-2026-30869) -\u003e fix `bb481e1` / `d68bd5a` (GHSA-6865-qjcf-286f): guards on\n  the main branch + `IsSensitivePath` extended to `*.db`/`*.log`.\n- Follow-up CVE-2026-41894 (GHSA-hjh7-r5w8-5872) in the same `/export` path family.\n- The `/export/temp/` short-circuit branch was never covered by the guards (this report).\n\n## Proof of concept (benign)\n1. Authenticate (access auth code).\n2. `GET /export/\u003csensitive\u003e` (main branch) -\u003e 401/403 (guards work).\n3. `GET /export/temp/%2e%2e/%2e%2e/.../tmp/\u003cplanted-marker\u003e` (or `/etc/hostname`) -\u003e 200 + file content,\n   demonstrating the unguarded traversal. The PoC reads only a planted marker / `/etc/hostname`; no credentials.\n\n## Impact\nAuthenticated arbitrary file read bypassing the sensitive-file protection: `/etc/passwd`, `~/.ssh/*`, SiYuan\n`*.db` workspace data, `*.log`. \n\n## Remediation\n- Apply `IsSubPath` + `IsSensitivePath` to the `/export/temp/` branch (or restrict its root to `TempDir/temp` with\n  an `IsSubPath` check).\n- `filepath.Clean` the request path and reject `..`.\n- Merge both branches into one guarded file-serving function.\n\n## References\n- Hardening advisory: https://github.com/siyuan-note/siyuan/security/advisories/GHSA-6865-qjcf-286f (commit d68bd5a); issue #12213.\n- CVE chain: CVE-2026-30869 -\u003e CVE-2026-41894 (GHSA-hjh7-r5w8-5872).\n- serve.go guards commit: https://github.com/siyuan-note/siyuan/commit/bb481e1290c4a34255652ede85a546504505d2a7\n- Residual source (master): `kernel/server/serve.go` `serveExport()` lines 308-312.",
  "id": "GHSA-gw25-m53r-qh88",
  "modified": "2026-09-03T14:56:31Z",
  "published": "2026-09-03T14:56:31Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-gw25-m53r-qh88"
    },
    {
      "type": "WEB",
      "url": "https://github.com/siyuan-note/siyuan/commit/b763d787d1f2b862c577049e4ee147c5857fe413"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/siyuan-note/siyuan"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "SiYuan: path traversal via /export/temp/ short-circuit branch (incomplete fix for the export-disclosure hardening, GHSA-6865-qjcf-286f)"
}



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