CVE-2024-40961: 
Linux Kernel vulnerability analysis and mitigation

CVE-2024-40961 is a vulnerability in the Linux kernel's IPv6 implementation that could lead to a NULL pointer dereference in the fib6nhinit() function. The vulnerability was discovered when syzbot identified that in6devget() can return NULL, which wasn't properly handled in the code (Kernel Patch). This issue affects Linux kernel versions from 4.17 up to versions before 6.9.7 (NVD).

The vulnerability occurs in the IPv6 routing functionality where the fib6nhinit() function fails to properly check for NULL return values from in6devget(). When calling ip6validategw() and ip6routechecknh(), the code assumes idev is not NULL. This can lead to a general protection fault when attempting to access the cnf.disableipv6 member of a NULL pointer (Kernel Patch). The vulnerability has been assigned a CVSS v3.1 base score of 5.5 (Medium) with vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H (NVD).

The vulnerability can result in a kernel crash (denial of service) when attempting to access invalid memory locations. This occurs due to a NULL pointer dereference, which triggers a general protection fault in the kernel (Kernel Patch).

The vulnerability has been fixed in the Linux kernel through a patch that adds proper NULL pointer checking before accessing the idev structure. The fix has been backported to multiple stable kernel versions. Users should update their kernel to versions that include the fix (Kernel Patch).