CVE-2019-11477 — AI Deep Analysis Summary

Q: What is this vulnerability? (Essence + Consequences)

🚨 **Essence**: A critical input validation flaw in the Linux Kernel's TCP SACK handling. 📉 **Consequences**: Triggers a Denial of Service (DoS). The system crashes or hangs, making services unavailable. 💥

Q: Root Cause? (CWE/Flaw)

🛡️ **Root Cause**: CWE-190 (Integer Overflow). The kernel mishandles TCP Selective Acknowledgment (SACK) fragments. ❌ **Flaw**: Incorrect input validation leads to memory corruption or infinite loops. 🐛

Q: Who is affected? (Versions/Components)

🌍 **Affected**: Linux Kernel (Linux Foundation). 📦 **Component**: Network Subsystem (TCP Stack). ⚠️ **Scope**: All vulnerable kernel versions prior to the fix. 🖥️

Q: What can hackers do? (Privileges/Data)

🕵️ **Hackers' Power**: Remote attackers. 🚫 **Action**: Cause DoS. 📉 **Impact**: System unresponsiveness. 🔒 **Privilege**: No RCE mentioned, just service disruption. 🛑

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

⚡ **Threshold**: Low. 🌐 **Auth**: None required (Remote). ⚙️ **Config**: Exploits TCP traffic. 🎯 **Ease**: Simple network packet crafting. 📡

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

🔓 **Public Exp?**: YES. 📂 **PoC**: Available on GitHub (sasqwatch/cve-2019-11477-poc). 🛠️ **Details**: Requires VM setup, netfilter modules, and crafting tools. 🧪

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

🔍 **Self-Check**: Scan for vulnerable kernel versions. 📡 **Detection**: Monitor for TCP SACK-related crashes. 🛠️ **Tools**: Use network scanners to identify unpatched hosts. 📋

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

✅ **Fixed**: YES. 📜 **Patch**: Vendor advisories exist (e.g., Red Hat RHSA-2019:1594). 🔄 **Action**: Update Linux Kernel immediately. 🛡️

Q: What if no patch? (Workaround)

🚧 **No Patch?**: Limit TCP traffic. 🚫 **Mitigation**: Block external TCP connections if possible. 🛡️ **Workaround**: Apply firewall rules to restrict SACK exposure. 📉

Q: Is it urgent? (Priority Suggestion)

🔥 **Urgency**: HIGH. 🚨 **Priority**: Critical DoS risk. ⏳ **Time**: Patch ASAP. 📢 **Alert**: Widespread impact on Linux servers. 🚀

Updated May 08, 2026

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**: A critical input validation flaw in the Linux Kernel's TCP SACK handling. 📉 **Consequences**: Triggers a Denial of Service (DoS). The system crashes or hangs, making services unavailable. 💥

Q2Root Cause? (CWE/Flaw)

🛡️ **Root Cause**: CWE-190 (Integer Overflow). The kernel mishandles TCP Selective Acknowledgment (SACK) fragments. ❌ **Flaw**: Incorrect input validation leads to memory corruption or infinite loops. 🐛

Q3Who is affected? (Versions/Components)

🌍 **Affected**: Linux Kernel (Linux Foundation). 📦 **Component**: Network Subsystem (TCP Stack). ⚠️ **Scope**: All vulnerable kernel versions prior to the fix. 🖥️

Q4What can hackers do? (Privileges/Data)

🕵️ **Hackers' Power**: Remote attackers. 🚫 **Action**: Cause DoS. 📉 **Impact**: System unresponsiveness. 🔒 **Privilege**: No RCE mentioned, just service disruption. 🛑

Q5Is exploitation threshold high? (Auth/Config)

⚡ **Threshold**: Low. 🌐 **Auth**: None required (Remote). ⚙️ **Config**: Exploits TCP traffic. 🎯 **Ease**: Simple network packet crafting. 📡

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

🔓 **Public Exp?**: YES. 📂 **PoC**: Available on GitHub (sasqwatch/cve-2019-11477-poc). 🛠️ **Details**: Requires VM setup, netfilter modules, and crafting tools. 🧪

Q7How to self-check? (Features/Scanning)

🔍 **Self-Check**: Scan for vulnerable kernel versions. 📡 **Detection**: Monitor for TCP SACK-related crashes. 🛠️ **Tools**: Use network scanners to identify unpatched hosts. 📋

Q8Is it fixed officially? (Patch/Mitigation)

✅ **Fixed**: YES. 📜 **Patch**: Vendor advisories exist (e.g., Red Hat RHSA-2019:1594). 🔄 **Action**: Update Linux Kernel immediately. 🛡️

Q9What if no patch? (Workaround)

🚧 **No Patch?**: Limit TCP traffic. 🚫 **Mitigation**: Block external TCP connections if possible. 🛡️ **Workaround**: Apply firewall rules to restrict SACK exposure. 📉

Q10Is it urgent? (Priority Suggestion)

🔥 **Urgency**: HIGH. 🚨 **Priority**: Critical DoS risk. ⏳ **Time**: Patch ASAP. 📢 **Alert**: Widespread impact on Linux servers. 🚀

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Vulnerability detail Full AI analysis (login) Linux CWE-190