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How the mentioned CVE works:
The vulnerability exists in the Linux kernel’s `lib/alloc_tag` component. The function `alloc_tag_top_users()` incorrectly attempts to acquire a semaphore (mod_lock) by dereferencing the `alloc_tag_cttype` pointer without first verifying if the pointer is valid. This pointer is NULL when memory profiling is disabled or if the alloc_tag subsystem failed to initialize properly. When the kernel encounters a memory allocation failure, it calls functions that eventually lead to alloc_tag_top_users(). This function then tries to access the non-existent semaphore located at an offset within the NULL pointer, causing a general protection fault and a kernel crash. This flaw allows a local user to induce a denial-of-service condition by triggering specific memory allocation failure paths.
DailyCVE Form:
Platform: Linux Kernel
Version: Up to 6.16.0-rc2
Vulnerability: NULL Dereference
Severity: Critical
Date: 2025-08-16
Prediction: 2025-10-16
What Undercode Say:
`cat /proc/meminfo`
`dmesg | grep “general protection fault”`
`echo 1 > /proc/sys/vm/panic_on_oom`
How Exploit:
Trigger memory exhaustion.
Force slab allocation failures.
Exploit boot-time conditions.
Protection from this CVE:
Apply kernel patch.
Update kernel version.
Disable mem profiling.
Impact:
Kernel panic.
System crash.
Denial-of-service.
🎯Let’s Practice Exploiting & Learn Patching For Free:
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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