CVE Catalog

CVE-2026-98011

Unknown
Published: Translated: NVD NIST

Summary

In the Linux kernel, hhf_change() accepted any quantum value from userspace, including 1. With a crafted size table qdisc_pkt_len reached ~2 GiB, so quantum=1 made the deficit-refill loop spin ~2^31 times under the qdisc lock, causing a soft lockup and denial of service.

Risk Assessment

A local attacker with CAP_NET_ADMIN privileges (obtainable in a namespace via unshare -Urn) can trigger a system hang through a soft lockup, causing denial of service.

Recommendation

Update the Linux kernel to a version containing the fix that adds max(256U, ...) in hhf_change() and clamps hhf_init() to [256, 1<<20], matching fq_codel_change().

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: net/sched: hhf: clamp quantum in change and init paths hhf_change() accepts any quantum from userspace, including 1. With a crafted size table qdisc_pkt_len reaches ~2 GiB, so quantum=1 makes the deficit-refill loop spin ~2^31 times under the qdisc lock (a soft lockup / denial of service). Add max(256U, ...) in hhf_change() matching fq_codel_change(). Clamp hhf_init() to [256, 1<<20] matching the siblings, and remove the old fallback that only set quantum=256 on overflow. Conditions to recreate the bug: CONFIG_NET_SCH_HHF=y. Requires CAP_NET_ADMIN (namespace-local via unshare -Urn suffices). tc qdisc add dev dummy0 root hhf tc qdisc change dev dummy0 root hhf quantum 1 stab data 32768 size_log 15 cell_log 0

Vulnerability data from NVD (NIST) · CISA KEV · EPSS