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CVE-2026-63983

Опубликовано: 19 июл. 2026
Источник: redhat
CVSS3: 5.5
EPSS Низкий

Описание

In the Linux kernel, the following vulnerability has been resolved: net/sched: fix packet loop on netem when duplicate is on When netem duplicates a packet it re-enqueues the copy at the root qdisc. If another netem sits in the tree the copy can be duplicated again, recursing until the stack or memory is exhausted. The original duplication guard temporarily zeroed q->duplicate around the re-enqueue, but that does not cover all cases because it is per-qdisc state shared across all concurrent enqueue paths and is not safe without additional locking. Use the skb tc_depth field introduced in an earlier patch:

  • increment it on the duplicate before re-enqueue
  • skip duplication for any skb whose tc_depth is already non-zero. This marks the packet itself rather than mutating qdisc state, therefore it is safe regardless of tree topology or concurrency.

    A flaw was found in the Linux kernel's network emulator (netem) component. This vulnerability occurs when netem duplicates a packet and re-enqueues it, leading to a recursive packet duplication loop if multiple netem instances are configured. This uncontrolled recursion can exhaust system resources, such as memory or stack, resulting in a Denial of Service (DoS) for the affected system.

Затронутые пакеты

ПлатформаПакетСостояниеРекомендацияРелиз
Red Hat Enterprise Linux 10kernelFix deferred
Red Hat Enterprise Linux 6kernelOut of support scope
Red Hat Enterprise Linux 7kernelFix deferred
Red Hat Enterprise Linux 7kernel-rtFix deferred
Red Hat Enterprise Linux 8kernelFix deferred
Red Hat Enterprise Linux 8kernel-rtFix deferred
Red Hat Enterprise Linux 9kernelFix deferred
Red Hat Enterprise Linux 9kernel-rtFix deferred

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Дополнительная информация

Статус:

Moderate
Дефект:
CWE-835
https://bugzilla.redhat.com/show_bug.cgi?id=2502372kernel: net/sched: fix packet loop on netem when duplicate is on

EPSS

Процентиль: 6%
0.00166
Низкий

5.5 Medium

CVSS3

Связанные уязвимости

ubuntu
13 дней назад

In the Linux kernel, the following vulnerability has been resolved: net/sched: fix packet loop on netem when duplicate is on When netem duplicates a packet it re-enqueues the copy at the root qdisc. If another netem sits in the tree the copy can be duplicated again, recursing until the stack or memory is exhausted. The original duplication guard temporarily zeroed q->duplicate around the re-enqueue, but that does not cover all cases because it is per-qdisc state shared across all concurrent enqueue paths and is not safe without additional locking. Use the skb tc_depth field introduced in an earlier patch: - increment it on the duplicate before re-enqueue - skip duplication for any skb whose tc_depth is already non-zero. This marks the packet itself rather than mutating qdisc state, therefore it is safe regardless of tree topology or concurrency.

nvd
13 дней назад

In the Linux kernel, the following vulnerability has been resolved: net/sched: fix packet loop on netem when duplicate is on When netem duplicates a packet it re-enqueues the copy at the root qdisc. If another netem sits in the tree the copy can be duplicated again, recursing until the stack or memory is exhausted. The original duplication guard temporarily zeroed q->duplicate around the re-enqueue, but that does not cover all cases because it is per-qdisc state shared across all concurrent enqueue paths and is not safe without additional locking. Use the skb tc_depth field introduced in an earlier patch: - increment it on the duplicate before re-enqueue - skip duplication for any skb whose tc_depth is already non-zero. This marks the packet itself rather than mutating qdisc state, therefore it is safe regardless of tree topology or concurrency.

msrc
12 дней назад

net/sched: fix packet loop on netem when duplicate is on

debian
13 дней назад

In the Linux kernel, the following vulnerability has been resolved: n ...

github
13 дней назад

In the Linux kernel, the following vulnerability has been resolved: net/sched: fix packet loop on netem when duplicate is on When netem duplicates a packet it re-enqueues the copy at the root qdisc. If another netem sits in the tree the copy can be duplicated again, recursing until the stack or memory is exhausted. The original duplication guard temporarily zeroed q->duplicate around the re-enqueue, but that does not cover all cases because it is per-qdisc state shared across all concurrent enqueue paths and is not safe without additional locking. Use the skb tc_depth field introduced in an earlier patch: - increment it on the duplicate before re-enqueue - skip duplication for any skb whose tc_depth is already non-zero. This marks the packet itself rather than mutating qdisc state, therefore it is safe regardless of tree topology or concurrency.

EPSS

Процентиль: 6%
0.00166
Низкий

5.5 Medium

CVSS3