CVE-2024-39485
📋 TL;DR
This CVE describes a use-after-free vulnerability in the Linux kernel's V4L (Video for Linux) async subsystem. When a notifier is unregistered, dangling pointers remain in the notifier_entry list, which could lead to memory corruption. This affects any Linux system using V4L2 video device drivers.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic, system crash, or potential local privilege escalation if an attacker can trigger the dangling pointer dereference to execute arbitrary code.
Likely Case
System instability, kernel crashes, or denial of service when video devices are frequently registered/unregistered.
If Mitigated
Minimal impact if systems don't heavily use V4L2 video devices or have proper kernel hardening.
🎯 Exploit Status
Requires local access and ability to trigger V4L notifier unregistration. No public exploits known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits 1aa6cd4adfc0380fa1ccc2f146848940ff882a66, 87100b09246202a91fce4a1562955c32229173bb, or 9537a8425a7a0222999d5839a0b394b1e8834b4a
Vendor Advisory: https://git.kernel.org/stable/c/1aa6cd4adfc0380fa1ccc2f146848940ff882a66
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. For distributions: Use package manager (apt/yum/dnf) to update kernel package. 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Disable V4L2 video devices
linuxRemove or blacklist V4L2 video drivers if not needed
modprobe -r <v4l2_driver_module>
echo 'blacklist <v4l2_driver_module>' >> /etc/modprobe.d/blacklist.conf
🧯 If You Can't Patch
- Restrict local user access to systems with video devices
- Implement kernel hardening features like KASLR and strict memory protections
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if V4L2 modules are loaded: 'lsmod | grep v4l2' and 'uname -r'Check Version:
uname -rVerify Fix Applied:
Verify kernel version contains fix commits: 'git log --oneline | grep -E "1aa6cd4|87100b09|9537a842"' on kernel source, or check distribution patch notes📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages in /var/log/kern.log or dmesg
- System crashes when using video devices
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kern.log" AND "Oops" AND "v4l2" OR "async"🔗 References
- https://git.kernel.org/stable/c/1aa6cd4adfc0380fa1ccc2f146848940ff882a66
- https://git.kernel.org/stable/c/87100b09246202a91fce4a1562955c32229173bb
- https://git.kernel.org/stable/c/9537a8425a7a0222999d5839a0b394b1e8834b4a
- https://git.kernel.org/stable/c/1aa6cd4adfc0380fa1ccc2f146848940ff882a66
- https://git.kernel.org/stable/c/87100b09246202a91fce4a1562955c32229173bb
- https://git.kernel.org/stable/c/9537a8425a7a0222999d5839a0b394b1e8834b4a
