CVE-2024-56534
📋 TL;DR
This CVE describes a memory leak vulnerability in the Linux kernel's isofs filesystem module. When mounting ISO filesystems with specific iocharset parameters, memory allocated for character set encoding isn't properly freed in error conditions, leading to gradual memory exhaustion. This affects Linux systems using the isofs module to mount ISO filesystems.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Sustained exploitation could lead to kernel memory exhaustion, causing system instability, crashes, or denial of service through resource depletion.
Likely Case
Gradual memory leak during repeated ISO filesystem mount operations with specific parameters, potentially affecting system performance over time.
If Mitigated
Minimal impact with proper monitoring and limited ISO mounting operations; memory eventually reclaimed on system reboot.
🎯 Exploit Status
Requires ability to mount ISO filesystems with specific parameters; memory leak is gradual rather than immediate exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in kernel commits: 0b5bbeee4de616a268db77e2f40f19ab010a367b, 0fbab266ca8000333c966f5b58cb9b9cac658573, 34f090ddb3630a26e5a6b220bf3bfaf5c7b70393
Vendor Advisory: https://git.kernel.org/stable/c/0b5bbeee4de616a268db77e2f40f19ab010a367b
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version. 2. Check with distribution vendor for specific kernel package updates. 3. Reboot system after kernel update.
🔧 Temporary Workarounds
Disable isofs module
linuxPrevent loading of vulnerable isofs kernel module
echo 'install isofs /bin/false' >> /etc/modprobe.d/disable-isofs.conf
rmmod isofs
Restrict ISO mounting
linuxLimit ability to mount ISO filesystems to trusted users only
chmod 750 /bin/mount
setfacl -m u:trusteduser:rx /bin/mount
🧯 If You Can't Patch
- Monitor system memory usage for unusual increases during ISO mounting operations
- Implement strict access controls on mount command usage and ISO file handling
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if isofs module is loaded: lsmod | grep isofsCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes patches or test mounting ISO with iocharset parameter while monitoring memory📡 Detection & Monitoring
Log Indicators:
- Kernel oom-killer messages
- System memory exhaustion warnings
- Repeated ISO mount operations in system logs
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("out of memory" OR "oom-killer") AND process="mount"