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How the mentioned CVE works:
The CVE-2025-38381 vulnerability exists within the `cs40l50_upload_owt()` function of the `cs40l50-vibra` haptic driver in the Linux kernel. The function dynamically allocates a kernel memory buffer using kmalloc(). However, the code does not check if the memory allocation was successful before proceeding to use the returned pointer. If `kmalloc()` fails and returns a NULL pointer, the subsequent code attempts to write data to this NULL memory address. This causes a kernel NULL pointer dereference, leading to a system crash or a kernel panic, denying service to the user.
DailyCVE Form:
Platform: Linux Kernel
Version: Affected versions
Vulnerability: NULL Dereference
Severity: Medium
date: 07/25/2025
Prediction: Patch expected by 08/08/2025
What Undercode Say:
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grep -r "cs40l50_upload_owt" /usr/src/linux-headers-$(uname -r)/ dmesg | grep -i "Oops|kernel panic" cat /proc/vmallocinfo
// Code snippet showing the vulnerable pattern buffer = kmalloc(size, GFP_KERNEL); memcpy(buffer, user_data, size); // Potential crash here if buffer is NULL
How Exploit:
A local user can trigger this flaw by invoking the driver’s firmware upload mechanism, often accessible via sysfs or a character device. By attempting to upload a custom waveform table (OWT) at a moment of extreme memory pressure, an attacker can induce the allocation failure. The subsequent NULL pointer dereference will cause a kernel panic, resulting in a denial-of-service (DoS) condition.
Protection from this CVE
Update the kernel.
Check kernel logs.
Avoid unnecessary modules.
Impact:
Denial-of-Service (DoS)
System crash.
Kernel panic.
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Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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