CVE-2022-50333
📋 TL;DR
This CVE-2022-50333 is a Linux kernel vulnerability in the JFS filesystem's dbDiscardAG function where improper bounds checking allows shift-out-of-bounds operations. Attackers could potentially crash the kernel or achieve local privilege escalation by feeding malicious input to the bmap descriptor. Systems using the JFS filesystem with affected Linux kernel versions 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 local privilege escalation allowing full system compromise.
Likely Case
Kernel crash causing denial of service and potential data corruption in JFS filesystems.
If Mitigated
Limited impact with proper kernel hardening and JFS filesystem isolation.
🎯 Exploit Status
Requires local access and ability to manipulate JFS filesystem operations; discovered by syzbot fuzzing.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Multiple stable kernel versions with commits: 0183c8f46ab5bcd0740f41c87f5141c6ca2bf1bb, 10b87da8fae79c7daf5eda6a9e4f1d31b85b4d92, 25e70c6162f207828dd405b432d8f2a98dbf7082, 3d340b684dcec5e34efc470227cd1c7d2df121ad, 50163a115831ef4e6402db5a7ef487d1989d7249
Vendor Advisory: https://git.kernel.org/stable/c/
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution's repository. 2. Reboot system to load new kernel. 3. Verify JFS filesystem functionality post-update.
🔧 Temporary Workarounds
Disable JFS filesystem
linuxPrevent loading of JFS kernel module to eliminate attack surface
echo 'blacklist jfs' >> /etc/modprobe.d/blacklist-jfs.conf
rmmod jfs
Mount JFS with noexec option
linuxReduce attack surface by preventing execution from JFS filesystems
mount -o remount,noexec /path/to/jfs/mountpoint
🧯 If You Can't Patch
- Implement strict access controls to limit who can mount or access JFS filesystems
- Monitor system logs for kernel panic events or JFS-related errors
🔍 How to Verify
Check if Vulnerable:
Check if JFS filesystem is in use: 'mount | grep -i jfs' or 'lsmod | grep jfs'Check Version:
uname -rVerify Fix Applied:
Check kernel version against patched versions from distribution vendor; verify JFS module loads without errors📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- JFS filesystem errors in dmesg
- System crash/reboot events
Network Indicators:
- None - local exploit only
SIEM Query:
source="kernel" AND ("panic" OR "Oops" OR "JFS" AND "error")🔗 References
- https://git.kernel.org/stable/c/0183c8f46ab5bcd0740f41c87f5141c6ca2bf1bb
- https://git.kernel.org/stable/c/10b87da8fae79c7daf5eda6a9e4f1d31b85b4d92
- https://git.kernel.org/stable/c/25e70c6162f207828dd405b432d8f2a98dbf7082
- https://git.kernel.org/stable/c/3d340b684dcec5e34efc470227cd1c7d2df121ad
- https://git.kernel.org/stable/c/50163a115831ef4e6402db5a7ef487d1989d7249
- https://git.kernel.org/stable/c/624843f1bac448150f6859999c72c4841c14a2e3
- https://git.kernel.org/stable/c/911999b193735cd378517b6cd5fe585ee345d49c
- https://git.kernel.org/stable/c/ab5cd3d62c2493eca3337e7d0178cc7bd819ca64
- https://git.kernel.org/stable/c/f8d4d0bac603616e2fa4a3907e81ed13f8f3c380
