CVE-2025-39849
📋 TL;DR
This CVE describes a memory corruption vulnerability in the Linux kernel's WiFi subsystem where SSID length validation is missing in the __cfg80211_connect_result() function. Attackers could exploit this to cause kernel memory corruption, potentially leading to system crashes or arbitrary code execution. All Linux systems using the affected WiFi subsystem are vulnerable.
💻 Affected Systems
- Linux kernel
📦 What is this software?
Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →⚠️ Risk & Real-World Impact
Worst Case
Kernel memory corruption leading to arbitrary code execution with kernel privileges, complete system compromise, or persistent denial of service.
Likely Case
System crashes, kernel panics, or denial of service affecting WiFi connectivity on vulnerable systems.
If Mitigated
Minimal impact with proper kernel hardening and exploit mitigations in place, though crashes may still occur.
🎯 Exploit Status
Exploitation requires ability to send crafted WiFi packets or control access point SSID. No public exploit code known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Multiple stable kernel versions with commits: 31229145e6ba5ace3e9391113376fa05b7831ede, 5cb7cab7adf9b1e6a99e2081b0e30e9e59d07523, 62b635dcd69c4fde7ce1de4992d71420a37e51e3, 8e751d46336205abc259ed3990e850a9843fb649, e472f59d02c82b511bc43a3f96d62ed08bf4537f
Vendor Advisory: https://git.kernel.org/stable/c/31229145e6ba5ace3e9391113376fa05b7831ede
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution's repositories. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable WiFi interfaces
linuxTemporarily disable WiFi functionality to prevent exploitation
sudo ip link set wlan0 down
sudo rfkill block wifi
Use wired networking only
linuxDisconnect from WiFi networks and use Ethernet connections exclusively
🧯 If You Can't Patch
- Disable WiFi functionality completely on affected systems
- Implement network segmentation to isolate WiFi networks from critical systems
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with patched versions from kernel git repository. Systems with unpatched kernels that have WiFi enabled are vulnerable.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes one of the fix commits: 31229145e6ba5ace3e9391113376fa05b7831ede or related patches📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- Oops messages in dmesg
- WiFi connection failures with unusual SSID lengths
Network Indicators:
- Unusual WiFi packets with SSID lengths exceeding 32 bytes
- Malformed 802.11 management frames
SIEM Query:
source="kernel" AND ("panic" OR "Oops" OR "BUG") AND ("cfg80211" OR "wifi" OR "802.11")🔗 References
- https://git.kernel.org/stable/c/31229145e6ba5ace3e9391113376fa05b7831ede
- https://git.kernel.org/stable/c/5cb7cab7adf9b1e6a99e2081b0e30e9e59d07523
- https://git.kernel.org/stable/c/62b635dcd69c4fde7ce1de4992d71420a37e51e3
- https://git.kernel.org/stable/c/8e751d46336205abc259ed3990e850a9843fb649
- https://git.kernel.org/stable/c/e472f59d02c82b511bc43a3f96d62ed08bf4537f
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
