Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-08-22T00:00:00 kernel: net/sched: sch_cake: drop WARN_ON(1) for malformed packets in ACK filter 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CWE-617

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.

A flaw was found in the Linux kernel. The sch_cake ACK filter, responsible for processing network packets, contains a vulnerability. A remote attacker could send specially crafted malformed IP packets. This could lead to the system logging excessive warnings or, under specific configurations, cause a system crash, resulting in a Denial of Service (DoS).

Red Hat Enterprise Linux 10 Fix deferred kernel Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Fix deferred kernel Red Hat Enterprise Linux 9 Fix deferred kernel-rt https://www.cve.org/CVERecord?id=CVE-2026-74704 https://nvd.nist.gov/vuln/detail/CVE-2026-74704 https://lore.kernel.org/linux-cve-announce/2026082236-CVE-2026-74704-ab92@gregkh/T