CVE-2023-52983
📋 TL;DR
This is a use-after-free vulnerability in the Linux kernel's BFQ I/O scheduler that could allow local attackers to crash the system or potentially execute arbitrary code with kernel privileges. It affects Linux systems using the BFQ scheduler, primarily impacting servers and workstations. The vulnerability occurs when freed memory is accessed through the bic_set_bfqq() function.
💻 Affected Systems
- Linux kernel with BFQ scheduler enabled
📦 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
Local privilege escalation to kernel-level access leading to complete system compromise, data theft, or persistent backdoor installation.
Likely Case
Kernel panic or system crash causing denial of service and potential data corruption.
If Mitigated
Limited impact due to SELinux/AppArmor restrictions or container isolation, but still risk of container escape in shared environments.
🎯 Exploit Status
Requires local access and knowledge of kernel exploitation techniques. No public exploit code known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits: 511c922c5bf6c8a166bea826e702336bc2424140, 7f77f3dab5066a7c9da73d72d1eee895ff84a8d5, b600de2d7d3a16f9007fad1bdae82a3951a26af2, cb1876fc33af26d00efdd473311f1b664c77c44e
Vendor Advisory: https://git.kernel.org/stable/c/511c922c5bf6c8a166bea826e702336bc2424140
Restart Required: Yes
Instructions:
1. Update kernel to patched version from your distribution's repositories. 2. Reboot system to load new kernel. 3. Verify BFQ scheduler is not required for your workload; consider disabling if not needed.
🔧 Temporary Workarounds
Disable BFQ scheduler
LinuxSwitch to alternative I/O scheduler if BFQ is not required for your workload
echo deadline > /sys/block/[device]/queue/scheduler
echo noop > /sys/block/[device]/queue/scheduler
🧯 If You Can't Patch
- Restrict local user access to minimize attack surface
- Implement strict SELinux/AppArmor policies to limit kernel access
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if BFQ scheduler is enabled: grep CONFIG_IOSCHED_BFQ /boot/config-$(uname -r) && uname -rCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is after fix commits and BFQ scheduler status📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- Oops messages in dmesg
- System crash/reboot events
Network Indicators:
- None - local exploitation only
SIEM Query:
EventID=41 OR Source="kernel" AND Message="Oops" OR "panic"