CVE-2025-21855
📋 TL;DR
A use-after-free vulnerability in the Linux kernel's ibmvnic driver allows potential memory corruption when network packets are transmitted. This affects Linux systems using the ibmvnic driver, particularly on IBM Power Systems with virtual I/O servers. The vulnerability could lead to system crashes or potential code execution.
💻 Affected Systems
- Linux kernel with ibmvnic driver
📦 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash, or potential arbitrary code execution with kernel privileges resulting in complete system compromise.
Likely Case
System instability, kernel panics, or denial of service due to memory corruption during network operations.
If Mitigated
System remains stable with no impact if patched or if the vulnerable code path isn't triggered.
🎯 Exploit Status
Requires local access and ability to trigger network transmission operations. Race condition makes exploitation timing-dependent.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel versions containing commits: 093b0e5c90592773863f300b908b741622eef597, 25dddd01dcc8ef3acff964dbb32eeb0d89f098e9, 501ac6a7e21b82e05207c6b4449812d82820f306, abaff2717470e4b5b7c0c3a90e128b211a23da09, bdf5d13aa05ec314d4385b31ac974d6c7e0997c9
Vendor Advisory: https://git.kernel.org/stable/c/093b0e5c90592773863f300b908b741622eef597
Restart Required: No
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. For distributions: Use package manager (yum update kernel, apt-get upgrade linux-image, etc.). 3. For custom kernels: Apply the relevant git commits and rebuild.
🔧 Temporary Workarounds
Disable ibmvnic driver
LinuxTemporarily disable the vulnerable ibmvnic driver if alternative networking is available
echo 'blacklist ibmvnic' >> /etc/modprobe.d/blacklist-ibmvnic.conf
rmmod ibmvnic
🧯 If You Can't Patch
- Restrict network access to affected systems to minimize attack surface
- Monitor system logs for kernel panics or memory corruption warnings
🔍 How to Verify
Check if Vulnerable:
Check if ibmvnic module is loaded: lsmod | grep ibmvnic. Check kernel version against patched versions.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes the fix commits. Check dmesg for absence of ibmvnic-related use-after-free errors.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- KASAN reports of use-after-free in ibmvnic_xmit
- Memory corruption warnings in dmesg
Network Indicators:
- Unusual network disruptions on IBM Power Systems
SIEM Query:
source="kernel" AND ("ibmvnic" OR "use-after-free" OR "KASAN")🔗 References
- https://git.kernel.org/stable/c/093b0e5c90592773863f300b908b741622eef597
- https://git.kernel.org/stable/c/25dddd01dcc8ef3acff964dbb32eeb0d89f098e9
- https://git.kernel.org/stable/c/501ac6a7e21b82e05207c6b4449812d82820f306
- https://git.kernel.org/stable/c/abaff2717470e4b5b7c0c3a90e128b211a23da09
- https://git.kernel.org/stable/c/bdf5d13aa05ec314d4385b31ac974d6c7e0997c9
- https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html
