CVE-2025-22047
📋 TL;DR
This CVE involves a logic error in the Linux kernel's AMD microcode update function where a failed SHA256 digest verification incorrectly returns true instead of false. This could allow corrupted or malicious microcode to be applied to AMD processors. All Linux systems with AMD CPUs using affected kernel versions are potentially 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 →⚠️ Risk & Real-World Impact
Worst Case
An attacker could load malicious microcode that causes system instability, denial of service, or potentially enables privilege escalation or data corruption.
Likely Case
System instability or crashes due to corrupted microcode being applied, leading to denial of service conditions.
If Mitigated
With proper access controls, the impact is limited to denial of service from system instability rather than privilege escalation.
🎯 Exploit Status
Exploitation requires local access and ability to trigger microcode updates, typically requiring elevated privileges.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits: 31ab12df723543047c3fc19cb8f8c4498ec6267f, 763f4d638f71cb45235395790a46e9f9e84227fd, 7f705a45f130a85fbf31c2abdc999c65644c8307, ada88219d5315fc13f2910fe278c7112d8d68889, d295c58fad1d5ab987a81f139dd21498732c4f13
Vendor Advisory: https://git.kernel.org/stable/c/31ab12df723543047c3fc19cb8f8c4498ec6267f
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 microcode update functionality works correctly.
🔧 Temporary Workarounds
Restrict microcode update permissions
linuxLimit access to microcode update mechanisms to prevent unauthorized updates
chmod 600 /sys/devices/system/cpu/microcode/reload
setfacl -m u:root:rw /sys/devices/system/cpu/microcode/reload
🧯 If You Can't Patch
- Implement strict access controls to prevent unauthorized users from triggering microcode updates
- Monitor system logs for microcode update attempts and system instability events
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with patched versions containing the fix commitsCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is updated and check that microcode update functionality returns correct error codes📡 Detection & Monitoring
Log Indicators:
- Failed microcode updates in kernel logs
- System instability or crashes after microcode updates
- Unauthorized access attempts to microcode update interfaces
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
source="kernel" AND ("microcode" OR "SHA256" OR "verify_sha256_digest") AND ("failed" OR "error")🔗 References
- https://git.kernel.org/stable/c/31ab12df723543047c3fc19cb8f8c4498ec6267f
- https://git.kernel.org/stable/c/763f4d638f71cb45235395790a46e9f9e84227fd
- https://git.kernel.org/stable/c/7f705a45f130a85fbf31c2abdc999c65644c8307
- https://git.kernel.org/stable/c/ada88219d5315fc13f2910fe278c7112d8d68889
- https://git.kernel.org/stable/c/d295c58fad1d5ab987a81f139dd21498732c4f13
