CVE-2026-31608 — AI Deep Analysis Summary

🚨 **Essence**: A critical **Double Free** bug in the Linux Kernel SMB Direct module. 📉 **Consequences**: `smb_direct_flush_send_list` calls `smb_direct_free_sendmsg` twice.…

🛠️ **Root Cause**: Logic error in memory management. The code fails to check if a message pointer is already freed before calling `free` again. 🧠 **Flaw**: Improper state tracking after the first flush operation.…

🌍 **Affected**: **Linux Kernel** (Open Source OS by Linux Foundation). 📦 **Component**: SMB Direct (SMB over RDMA) subsystem. ⚠️ **Scope**: All versions containing the vulnerable SMB Direct code path prior to the fix.

🔓 **Privileges**: **High**. CVSS Score indicates **Complete** impact on Confidentiality, Integrity, and Availability.…

⚡ **Threshold**: **Low**. 🌐 **Network**: Attack vector is **Network (AV:N)**. 🔑 **Auth**: **No Privileges Required (PR:N)**. 🤝 **User Interaction**: **None (UI:N)**.…

📜 **Public Exp**: **No PoC available** in the data. 🕵️ **Status**: References point to kernel git commits (fixes), but no public exploit code (PoC) is listed.…

🔍 **Check**: Scan for **SMB Direct** usage. 📡 **Features**: Look for RDMA-enabled SMB connections. 🛠️ **Tools**: Use kernel version scanners to identify unpatched Linux kernels.…

✅ **Fixed**: **Yes**. 📅 **Date**: Patched on **2026-04-24**. 📂 **Source**: Official Linux Kernel Stable Git commits (links provided).…

🚧 **Workaround**: Disable **SMB Direct (RDMA)** if not strictly needed. 🛑 **Mitigation**: Restrict network access to SMB ports. 🧱 **Firewall**: Block external access to RDMA-enabled interfaces.…

🔥 **Urgency**: **CRITICAL**. 🚨 **Priority**: **P1**. 📈 **CVSS**: High (H/H/H). ⏱️ **Time**: Immediate patching required. 🛡️ **Reason**: Remote, unauthenticated, high-impact RCE/DoS. Do not ignore!