CVE Catalog

CVE-2026-98013

Unknown
Published: Translated: NVD NIST

Summary

In the Linux kernel, fq_pie_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 clamps quantum to max(256U, ...) in fq_pie_change(), matching fq_codel_change().

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: net/sched: fq_pie: clamp quantum in change path fq_pie_change() accepts any quantum value 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, ...) matching fq_codel_change(). Conditions to recreate the bug: CONFIG_NET_SCH_FQ_PIE=y. Requires CAP_NET_ADMIN (namespace-local via unshare -Urn suffices). tc qdisc add dev dummy0 root fq_pie tc qdisc change dev dummy0 root fq_pie quantum 1 stab data 32768 size_log 15 cell_log 0

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