Question 1

What is this vulnerability? (Essence + Consequences)

Accepted Answer

🚨 **Essence**: SiYuan (v3.6.3 & earlier) renders Mermaid charts insecurely. SVGs are injected via `innerHTML`.
💥 **Consequences**: Attackers inject `javascript:` URLs.…

Question 2

Root Cause? (CWE/Flaw)

Accepted Answer

🛡️ **Root Cause**: **CWE-79** (Cross-site Scripting).
🔍 **Flaw**: Mermaid diagrams use a **loose security level**. Generated SVGs bypass sanitization and are directly injected into the DOM using `innerHTML`.

Question 3

Who is affected? (Versions/Components)

Accepted Answer

📦 **Affected**: **SiYuan Note** (Personal Knowledge Management).
📅 **Versions**: **3.6.3 and earlier**.
💻 **Platform**: Specifically critical in **Desktop Electron builds**.

Question 4

What can hackers do? (Privileges/Data)

Accepted Answer

🕵️ **Hackers Can**: Execute arbitrary JavaScript via `javascript:` URLs in Mermaid output.
🔓 **Privileges**: Escalate Stored XSS to **Remote Code Execution (RCE)** on the victim's machine.…

Question 5

Is exploitation threshold high? (Auth/Config)

Accepted Answer

⚖️ **Threshold**: **Medium**.
🔑 **Auth**: Requires **Low Privileges** (PR:L).
👁️ **UI**: Requires **User Interaction** (UI:R).
🌐 **Network**: Network Accessible (AV:N).

Question 6

Is there a public Exp? (PoC/Wild Exploitation)

Accepted Answer

🚫 **Public Exp?**: **No**.
📋 **PoC**: The `pocs` field is empty.
🔒 **Status**: No wild exploitation reported yet. Patch immediately to stay safe.

Question 7

How to self-check? (Features/Scanning)

Accepted Answer

🔍 **Self-Check**:
1. Check SiYuan version (≤ 3.6.3).
2. Look for Mermaid charts in notes.
3. Scan for `innerHTML` usage in SVG rendering logic.
4.…

Question 8

Is it fixed officially? (Patch/Mitigation)

Accepted Answer

✅ **Fixed?**: **Yes**.
📦 **Patch**: Upgrade to **v3.6.4**.…

Question 9

What if no patch? (Workaround)

Accepted Answer

🛡️ **No Patch?**:
1. **Disable Mermaid** rendering if possible.
2. **Isolate** the application (sandbox).
3. **Avoid** importing untrusted Markdown/Mermaid code.
4. Monitor for suspicious DOM injections.

Question 10

Is it urgent? (Priority Suggestion)

Accepted Answer

🔥 **Urgency**: **HIGH**.
⚠️ **Priority**: Critical due to **RCE potential** in Electron apps.
🚀 **Action**: Update to v3.6.4 **immediately**. CVSS Score is High (H/H/H).

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CVE-2026-40322 — AI Deep Analysis Summary

Q1What is this vulnerability? (Essence + Consequences)

Q2Root Cause? (CWE/Flaw)

Q3Who is affected? (Versions/Components)

Q4What can hackers do? (Privileges/Data)

Q5Is exploitation threshold high? (Auth/Config)

Q6Is there a public Exp? (PoC/Wild Exploitation)

Q7How to self-check? (Features/Scanning)

Q8Is it fixed officially? (Patch/Mitigation)

Q9What if no patch? (Workaround)

Q10Is it urgent? (Priority Suggestion)

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