CVE-2026-98009

/// Technical description

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

net/sched: ets: clamp quantum in parse and fallback paths

ets_qdisc_change() falls back to psched_mtu() with no floor for bands

without an explicit quantum. With a crafted size table qdisc_pkt_len

reaches ~2 GiB, so a zero psched_mtu on a headerless device makes the

deficit-refill loop spin under the qdisc lock.

Move the floor into ets_quantum_parse() so explicitly configured quanta

are also clamped to [256, 1<<20], not just the fallback path.

Conditions to recreate the bug:

CONFIG_NET_SCH_ETS=y. Requires CAP_NET_ADMIN (namespace-local via

unshare -Urn suffices).

tc qdisc add dev dummy0 root ets bands 3 strict 2 quanta 1 1

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References