User Event Memory Vulnerability in Linux Kernel Affecting Multiple Versions

CVE-2026-89750

What is CVE-2026-89750?

A use-after-free vulnerability exists in the Linux Kernel related to user event memory management. During the fork duplication process, the child process inherits a pointer to the parent’s user_event_mm structure without a proper reference. When the user_event_mm_alloc function fails, the state remains unchanged, leading to the possibility of the child process incorrectly freeing memory that the parent still references. This oversight results in a stale pointer being accessed, which can lead to severe memory corruption and system instability. The introduced fix ensures the copied pointer is properly cleared if a failure occurs, preventing erroneous memory access.

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