Linux Kernel Vulnerability Affecting Qdisc Hierarchy in Networking

CVE-2025-68325

What is CVE-2025-68325?

A vulnerability in the Linux kernel's networking subsystem affects the queuing discipline (qdisc) hierarchy, specifically in the cake scheduler. The issue arises during packet enqueueing in the cake_drop() function, which can lead to inconsistent queue length and backlog accounting due to an incorrect assumption about packet processing. When cake_enqueue() returns NET_XMIT_CN, the parent qdisc may halt enqueuing the current packet, causing a potential NULL dereference. A patch has been introduced to enhance the robustness of queue accounting by accurately computing the qlen/backlog delta, ensuring proper operation even with ACK thinning enabled.

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