Use-After-Free in Linux Kernel Pppol2tp Functionality

CVE-2026-68398

What is CVE-2026-68398?

The vulnerability within the Linux kernel occurs in the pppol2tp_recv() function, which fails to properly manage memory deallocation in a multi-threaded environment. This oversight allows an unprivileged user to potentially exploit the system by dereferencing a channel that has already been freed, leading to unpredictable behavior or system instability. The issue arises from inadequate synchronization during the tear-down of PPP connections, resulting in the possibility of data corruption or memory access violations. The resolution includes deferring memory release to ensure proper grace periods are adhered to, thereby safeguarding against concurrent access by multiple threads.

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