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How the mentioned CVE works
The CVE-2025-38518 vulnerability stems from a CPUID misreporting issue on a specific AMD Zen2 processor, the Cyan Skillfish (Family 17h, Model 47h). This faulty CPU incorrectly reports support for the INVLPGB instruction, an advanced feature for flushing the Translation Lookaside Buffer (TLB). The Linux kernel, trusting this CPUID information, subsequently uses the INVLPGB instruction for TLB maintenance on the affected system. However, the hardware does not properly execute the instruction, leading to system instability in the form of kernel oopses and panics when a TLB flush is required. The kernel’s resolution is to programmatically “zap” or ignore the INVLPGB capability bit for this specific CPU model, preventing its use and avoiding the instability.
DailyCVE
Platform: Linux Kernel
Version: x86/CPU/AMD
Vulnerability : INVLPGB Misreporting
Severity: Medium
date: 08/16/2025
Prediction: Patch expected by 08/30/2025
What Undercode Say:
Analytics
`grep -r “INVLPGB” /usr/src/linux-headers-$(uname -r)/`
`cat /proc/cpuinfo | grep -i “model name”`
`dmesg | grep -i “Oops\|panic”`
How Exploit:
N/A (System instability triggered by normal kernel operation on faulty hardware)
Protection from this CVE
Apply kernel patch.
Update to fixed kernel version.
Zap INVLPGB CPUID bit.
Impact:
Kernel oopses.
System panics.
Denial-of-service.
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Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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