Linux Kernel Vulnerability in ext4 Filesystem Affects Block Allocation

CVE-2026-43067

What is CVE-2026-43067?

In the Linux kernel, a vulnerability has been introduced in the ext4 filesystem's handling of block allocations for files that utilize indirect mapping. The allocation mechanism can mistakenly attempt to allocate blocks beyond the 32-bit limitation, particularly in scenarios where the filesystem contains both extent-mapped and indirect-block mapped files. This situation can arise if inappropriate group indices are utilized, leading to potential issues during block allocation. To mitigate this risk, a safety clamp has been proposed to ensure that block allocations are carried out within safe group limits.

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