CVE-2021-4477 — AI Deep Analysis Summary

Q: Root Cause? (CWE/Flaw)

🛡️ **CWE-284**: Improper Access Control. ❌ **Flaw**: The device fails to enforce firewall policies correctly when handling IPv6 IPsec traffic. The security boundary is breached at the network layer.

Q: Who is affected? (Versions/Components)

🏭 **Vendor**: Belden. 📦 **Product**: Hirschmann HiLCOS OpenBAT (Industrial Wireless LAN). ⚠️ **Scope**: Specifically affects deployments using **IPv6 IPsec** configurations.

Q: Is exploitation threshold high? (Auth/Config)

⚡ **Threshold**: LOW. 🔓 **Auth**: None required (PR:N). 🌐 **Access**: Network accessible (AV:N). 🎯 **Complexity**: Low (AC:L). No user interaction needed (UI:N). Easy to exploit remotely.

Q: How to self-check? (Features/Scanning)

🔍 **Check**: Scan for **Belden Hirschmann HiLCOS OpenBAT** devices. 📡 **Feature**: Verify if **IPv6 IPsec** is enabled. 🛠️ **Tool**: Use network scanners to identify the specific industrial wireless LAN hardware.

Q: Is it fixed officially? (Patch/Mitigation)

🩹 **Fix**: Yes, official vendor advisory exists. 📄 **Doc**: Belden Security Bulletin BSECV-1v0-2019-09. ✅ **Action**: Update firmware/software to the patched version provided by Belden.

Q: What if no patch? (Workaround)

🚧 **Workaround**: Disable **IPv6 IPsec** if not strictly necessary. 🔒 **Mitigation**: Implement strict network segmentation. Monitor VPN traffic logs for anomalies that bypass standard firewall rules.

Q: Is it urgent? (Priority Suggestion)

🔴 **Priority**: HIGH. 📈 **CVSS**: 9.1 (Critical). ⏱️ **Urgency**: Immediate patching recommended. Industrial control systems are high-value targets; bypassing firewalls is a critical security failure.

Updated May 06, 2026 CVSS 9.1 · Critical

This is a summary of the AI-generated 10-question deep analysis. The full version (longer answers, follow-up Q&A, related CVEs) requires login. Read the full analysis →

Q1What is this vulnerability? (Essence + Consequences)

🚨 **Essence**: Access Control Error in Belden Hirschmann HiLCOS OpenBAT. <br>🔥 **Consequences**: IPv6 IPsec deployment allows **Firewall Bypass**.…

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Q2Root Cause? (CWE/Flaw)

🛡️ **CWE-284**: Improper Access Control. <br>❌ **Flaw**: The device fails to enforce firewall policies correctly when handling IPv6 IPsec traffic. The security boundary is breached at the network layer.

Q3Who is affected? (Versions/Components)

🏭 **Vendor**: Belden. <br>📦 **Product**: Hirschmann HiLCOS OpenBAT (Industrial Wireless LAN). <br>⚠️ **Scope**: Specifically affects deployments using **IPv6 IPsec** configurations.

Q4What can hackers do? (Privileges/Data)

💻 **Hackers Can**: Bypass security filters. <br>📂 **Impact**: High Confidentiality & Integrity loss (CVSS C:H, I:H).…

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Q5Is exploitation threshold high? (Auth/Config)

⚡ **Threshold**: LOW. <br>🔓 **Auth**: None required (PR:N). <br>🌐 **Access**: Network accessible (AV:N). <br>🎯 **Complexity**: Low (AC:L). No user interaction needed (UI:N). Easy to exploit remotely.

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

🕵️ **Public Exploit**: No specific PoC listed in data. <br>📜 **References**: Vendor advisory (BSECV-1v0-2019-09) and VulnCheck report exist.…

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Q7How to self-check? (Features/Scanning)

🔍 **Check**: Scan for **Belden Hirschmann HiLCOS OpenBAT** devices. <br>📡 **Feature**: Verify if **IPv6 IPsec** is enabled. <br>🛠️ **Tool**: Use network scanners to identify the specific industrial wireless LAN hardware.

Q8Is it fixed officially? (Patch/Mitigation)

🩹 **Fix**: Yes, official vendor advisory exists. <br>📄 **Doc**: Belden Security Bulletin BSECV-1v0-2019-09. <br>✅ **Action**: Update firmware/software to the patched version provided by Belden.

Q9What if no patch? (Workaround)

🚧 **Workaround**: Disable **IPv6 IPsec** if not strictly necessary. <br>🔒 **Mitigation**: Implement strict network segmentation. Monitor VPN traffic logs for anomalies that bypass standard firewall rules.

Q10Is it urgent? (Priority Suggestion)

🔴 **Priority**: HIGH. <br>📈 **CVSS**: 9.1 (Critical). <br>⏱️ **Urgency**: Immediate patching recommended. Industrial control systems are high-value targets; bypassing firewalls is a critical security failure.

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Vulnerability detail Full AI analysis (login) Belden CWE-284