CVE-2024-56704
📋 TL;DR
This CVE describes a double-free vulnerability in the Linux kernel's 9p/xen subsystem where an IRQ (Interrupt Request) is incorrectly released twice. This can lead to memory corruption and potential kernel crashes or privilege escalation. Systems running affected Linux kernel versions with 9p filesystem support in Xen virtualization environments 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 panic leading to system crash, or privilege escalation allowing attackers to gain root access and execute arbitrary code.
Likely Case
System instability, kernel crashes, or denial of service affecting virtualized environments using 9p filesystem with Xen.
If Mitigated
Limited impact if system doesn't use 9p filesystem in Xen environments or has proper isolation between virtual machines.
🎯 Exploit Status
Requires local access to trigger the double-free condition. Exploitation would need to leverage the memory corruption for further attacks.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing the fix commits listed in references
Vendor Advisory: https://git.kernel.org/stable/c/2bb3ee1bf237557daea1d58007d2e1d4a6502ccf
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 9p filesystem in Xen
linuxPrevent use of vulnerable 9p filesystem in Xen virtualization environments
# Check if 9p is loaded: lsmod | grep 9p
# Remove module if loaded: sudo rmmod 9p
# Blacklist to prevent loading: echo 'blacklist 9p' | sudo tee /etc/modprobe.d/blacklist-9p.conf
🧯 If You Can't Patch
- Isolate systems using 9p/Xen from untrusted users and networks
- Implement strict access controls and monitoring on affected systems
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if 9p module is loaded: uname -r && lsmod | grep 9pCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is updated and check dmesg for absence of IRQ double-free errors📡 Detection & Monitoring
Log Indicators:
- Kernel logs showing 'IRQ double-freed' or similar errors
- System crashes or panics related to 9p or Xen subsystems
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
source="kernel" AND ("IRQ double-free" OR "9p" OR "Xen")🔗 References
- https://git.kernel.org/stable/c/2bb3ee1bf237557daea1d58007d2e1d4a6502ccf
- https://git.kernel.org/stable/c/4950408793b118cb8075bcee1f033b543fb719fa
- https://git.kernel.org/stable/c/530bc9f03a102fac95b07cda513bfc16ff69e0ee
- https://git.kernel.org/stable/c/692eb06703afc3e24d889d77e94a0e20229f6a4a
- https://git.kernel.org/stable/c/7f5a2ed5c1810661e6b03f5a4ebf17682cdea850
- https://git.kernel.org/stable/c/b9e26059664bd9ebc64a0e8f5216266fc9f84265
- https://git.kernel.org/stable/c/d74b4b297097bd361b8a9abfde9b521ff464ea9c
- https://git.kernel.org/stable/c/d888f5f5d76b2722c267e6bdf51d445d60647b7b
- https://git.kernel.org/stable/c/e43c608f40c065b30964f0a806348062991b802d
- https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html
- https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html
