CVE-2026-53079
Received Received - Intake
Memory Leak in Linux Kernel Network Scheduler

Publication date: 2026-06-24

Last updated on: 2026-06-24

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: net_sched: fix skb memory leak in deferred qdisc drops When the network stack cleans up the deferred list via qdisc_run_end(), it operates on the root qdisc. If the root qdisc do not implement the TCQ_F_DEQUEUE_DROPS flag the packets queue to free are never freed and gets stranded on the child's local to_free list. Fix this by making qdisc_dequeue_drop() aware of the root qdisc. It fetches the root qdisc and check for the TCQ_F_DEQUEUE_DROPS flag. If the flag is present, the packet is appended directly to the root's to_free list. Otherwise, drop it directly as it was done before the optimization was implemented.
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Meta Information
Published
2026-06-24
Last Modified
2026-06-24
Generated
2026-06-25
AI Q&A
2026-06-24
EPSS Evaluated
N/A
NVD
EUVD
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
linux_kernel linux_kernel *
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Exploitability
CWE
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KEV
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability exists in the Linux kernel's network scheduler (net_sched) where there is a memory leak related to skb (socket buffer) objects during deferred queueing discipline (qdisc) drops.

Specifically, when the network stack cleans up the deferred list using the function qdisc_run_end(), it operates on the root qdisc. If the root qdisc does not implement the TCQ_F_DEQUEUE_DROPS flag, packets that should be freed remain stranded on the child's local to_free list and are never actually freed, causing a memory leak.

The fix involves making the function qdisc_dequeue_drop() aware of the root qdisc by checking for the TCQ_F_DEQUEUE_DROPS flag. If the flag is present, packets are appended directly to the root's to_free list; otherwise, packets are dropped directly as before the optimization.

Impact Analysis

This vulnerability can lead to a memory leak in the Linux kernel's network stack, which means that memory allocated for network packets may not be properly freed.

Over time, this could cause increased memory usage, potentially degrading system performance or leading to resource exhaustion, which might result in network instability or crashes.

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