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CVE-2026-98013

net/sched: fq_pie: clamp quantum in change path PUBLISHED

Description (CNA)

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

Affected (CNA)

Vendor / productVersions
Linux / Linuxaffected ec97ecf1ebe485a17cd8395a5f35e6b80b57665a before ff4f3a0f3abd2ded467931d7da7984a68a768e0b; affected ec97ecf1ebe485a17cd8395a5f35e6b80b57665a before 749aaebc1eb92ce2f38fd3caf68a2f99686d84ef; affected ec97ecf1ebe485a17cd8395a5f35e6b80b57665a before 8fd98e56c41f79278eeb67512c28d7abc175bcf4; affected ec97ecf1ebe485a17cd8395a5f35e6b80b57665a before 215df1e953ae72a09d425ec188e054058ae23dc9; affected ec97ecf1ebe485a17cd8395a5f35e6b80b57665a before f90fe65b977e7aa9eb302230a09eb18f8c32ceaa; affected ec97ecf1ebe485a17cd8395a5f35e6b80b57665a before c11e3a39807eb5a200445ae9082843ab86800415; affected ec97ecf1ebe485a17cd8395a5f35e6b80b57665a before 6655b56e2801008566c594ef231f6c7b3f716c61; affected ec97ecf1ebe485a17cd8395a5f35e6b80b57665a before 4864f58c53eb47257d55e01f47d4a9f355f7f970
Linux / Linuxaffected 5.6; unaffected 0 before 5.6; unaffected 5.10.271 through 5.10.*; unaffected 5.15.222 through 5.15.*; unaffected 6.1.189 through 6.1.*; unaffected 6.6.158 through 6.6.*; unaffected 6.12.111 through 6.12.*; unaffected 6.18.53 through 6.18.*; unaffected 7.2.7 through 7.2.*; unaffected 7.3 through *

CWE

No CWE identifiers supplied.

References