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CVE-2026-40470 β€” AI Deep Analysis Summary

CVSS 9.9 Β· Critical

Q1What is this vulnerability? (Essence + Consequences)

🚨 **Essence**: hackage-server suffers from a **Cross-Site Scripting (XSS)** vulnerability. πŸ“‰ **Consequences**: Malicious HTML/JS files are served as-is.…

Q2Root Cause? (CWE/Flaw)

πŸ›‘οΈ **Root Cause**: **CWE-79** (Improper Neutralization of Input). The server fails to sanitize HTML and JavaScript content before serving it, allowing malicious scripts to execute in the victim's browser.

Q3Who is affected? (Versions/Components)

πŸ“¦ **Affected**: Users of **hackage-server**, the open-source Haskell package repository server. ⚠️ Specifically, scenarios where **malicious package maintainers** upload or serve compromised HTML/JS files.

Q4What can hackers do? (Privileges/Data)

πŸ’€ **Attacker Capabilities**: Hijack active user sessions. πŸ•΅οΈβ€β™‚οΈ Gain unauthorized access to user accounts. πŸ“‚ Potentially access sensitive data or perform actions on behalf of the victim.

Q5Is exploitation threshold high? (Auth/Config)

πŸ”“ **Exploitation Threshold**: **Medium**. Requires **PR:L** (Low Privileges) – likely needing access as a package maintainer or uploader.…

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

πŸ” **Public Exploit**: No specific PoC code provided in the data. However, the vulnerability class (Stored/Reflected XSS via file serving) is easily exploitable by any maintainer with upload rights.

Q7How to self-check? (Features/Scanning)

πŸ”Ž **Self-Check**: Scan for **hackage-server** instances. Check if uploaded package files (HTML/JS) are served with correct MIME types but **without content sanitization**.…

Q8Is it fixed officially? (Patch/Mitigation)

🩹 **Official Fix**: The vulnerability was published on **2026-04-23**. Refer to the reference link (HSEC-2024-0004) for the official patch or mitigation guidance from the maintainers.

Q9What if no patch? (Workaround)

🚧 **No Patch Workaround**: Implement a strict **Content Security Policy (CSP)**. Configure the server to enforce **Content-Type sniffing** restrictions. Sanitize all uploaded HTML/JS files before serving.

Q10Is it urgent? (Priority Suggestion)

πŸ”₯ **Urgency**: **High**. CVSS Score indicates **High** Confidentiality and Integrity impact. Session hijacking is critical. Immediate review of uploaded package contents and server configuration is recommended.