CVE-2026-31649 — AI Deep Analysis Summary

🚨 **Essence**: A critical integer underflow in the Linux kernel's `stmmac` driver (chain mode). 📉 **Consequences**: This flaw allows for **DMA mapping of arbitrary kernel memory**.…

🛡️ **Root Cause**: **Integer Underflow** 📉. Specifically within the `stmmac` driver's chain mode processing.…

🏢 **Vendor**: Linux Foundation. 🐧 **Product**: Linux Kernel. 📅 **Affected**: All versions prior to the stable fixes published on **2026-04-24**. 📦 Components: Network drivers utilizing `stmmac` in chain mode.

🔓 **Privileges**: **Root/Kernel Level**. 🕵️ **Actions**: Hackers can map **arbitrary kernel memory** via DMA. 📂 **Data**: Full read/write access to sensitive kernel structures.…

🔑 **Threshold**: **LOW**. 🌐 **Network**: Attack Vector is Network (AV:N). 🚫 **Auth**: No Privileges Required (PR:N). 👤 **User Interaction**: None (UI:N). 📉 **Complexity**: Low (AC:L). Easy to exploit remotely.

📜 **Public Exploit**: **None** currently listed in the data (POCs: []). 🔍 **Status**: While no PoC is public, the CVSS score (Critical) and low exploitation barrier suggest high risk of imminent wild exploitation.…

🔍 **Self-Check**: Scan for Linux Kernel versions released before **2026-04-24**. 📡 **Feature**: Check if `stmmac` driver is active and configured in **chain mode**.…

✅ **Fixed**: **YES**. 📅 **Patch Date**: 2026-04-24. 🔗 **Links**: Multiple stable commits available (e.g., `513e067`, `b7b8012`). 🔄 **Action**: Update Linux Kernel to the latest stable version immediately.

🚧 **Workaround**: If patching is impossible, **disable** or **unload** the `stmmac` driver if not strictly needed. 🚫 **Mitigation**: Restrict network access to the affected host.…

🔥 **Urgency**: **CRITICAL**. 🚨 **Priority**: **P0 / Immediate Action**. 📉 **CVSS**: 9.8 (Critical). 🛡️ **Reason**: Remote, no auth, low complexity, and full system compromise potential. Patch NOW.