Linux Kernel Vulnerability Affecting Block Layer Operations

CVE-2025-39999

What is CVE-2025-39999?

A vulnerability in the Linux kernel's block layer management can lead to a double free scenario when the number of request tags increases. Specifically, the issue arises in the blk-mq implementation where the scheduled tags management can lead to a kernel panic if not correctly handled. When users modify the 'nr_requests' sysfs attribute, it inadvertently frees the current allocated tags while mismanaging the pointers, creating a risk of two free operations on the same memory. A fix has been implemented to ensure proper allocation and management of tags, yet some underlying challenges may require future refactoring for a comprehensive resolution.

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