---
id: CVE-2026-74704
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/sched: sch_cake: drop WARN_ON(1) for malformed packets in ACK filter

  The sch_cake ACK filter parses packets to find the TCP header and filter
  duplicated ACKs if th…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/sched: sch_cake: drop WARN_ON(1) for malformed packets in ACK filter

  The sch_cake ACK filter parses packets to find the TCP header and filter
  duplicated ACKs if th…
severity: high
cvss: 8.2
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H'
published: '2026-08-22'
updated: '2026-10-14'
sourceUpdated: '2026-10-14T13:10:00.187'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-74704'
references:
  - url: 'https://git.kernel.org/stable/c/0c4882bff34558d8d53fb04c3e96da5c327c7dc8'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2504a76e5c0694e14e15562730e1339f2d9f9458'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2a33516f9ef59ad11844d4fc152f889449b5daf3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a1ae353d8355407c1bea971d1c1af5e7f242bb7d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a4b52612004a5639c4bfc30ba93ba414b8326e2a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ae1b2f8e21a41e7c7e75511bea0c4ccc59ec1bd3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c1693b7844a6c06d31a565e5a494948034dfd235'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cd2f1d9fe8a507c2dc86ad326fe221f121c47734'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00443
epssPercentile: 0.36746
ingestedAt: '2026-10-14T13:30:58.542Z'
---

## Overview

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

net/sched: sch_cake: drop WARN_ON(1) for malformed packets in ACK filter

The sch_cake ACK filter parses packets to find the TCP header and filter
duplicated ACKs if the flow is backlogged. The parsing code contains a
WARN_ON(1) which can be triggered by a malformed IP header in certain
cases. Depending on the system configuration, this leads either to
either spamming dmesg with warnings, or a panic if panic_on_warn is set.

The code already correctly skips the offending packet in the branch that
triggers the warning, so the WARN_ON itself doesn't really serve any
purpose. So just drop it altogether to avoid the inconvenient side
effects.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.