Network Scheduling Vulnerability in Linux Kernel Affecting DualPI2 Functionality

CVE-2026-64207

What is CVE-2026-64207?

In the Linux Kernel, a vulnerability related to the DualPI2 functionality has been identified, wherein GSO backlog accounting fails to accurately manage packet queuing. When DualPI2 disassembles a GSO SKB into multiple segments, it erroneously signals extra packets to its parent queue. This mismanagement leads to a discrepancy where the parent wrongly increments its queue length (qlen), resulting in a scenario where QFQ (a queueing discipline) still has a non-zero qlen despite no active classes being present. This can cause a NULL pointer dereference in the kernel as qfq_choose_next_agg() returns NULL, posing potential stability risks. A fix has been applied to ensure correct accounting and to propagate only the successfully queued segments.

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