CVE Catalog

CVE-2026-98010

Unknown
Published: Translated: NVD NIST

Summary

In the Linux kernel, drr_change_class() rejected explicit quantum==0 but otherwise fell back to psched_mtu() with no floor. With a crafted size table qdisc_pkt_len reached ~2 GiB, so quantum=1 (or a zero psched_mtu on a headerless device) made the deficit-refill loop spin 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 clamp_t(u32, quantum, 256, 1<<20) after the zero reject and on the fallback path in drr_change_class().

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: drr: clamp quantum in change class drr_change_class() rejects explicit quantum==0 but falls back to psched_mtu() with no floor. With a crafted size table qdisc_pkt_len reaches ~2 GiB, so quantum=1 (or a zero psched_mtu on a headerless device) makes the deficit-refill loop spin under the qdisc lock. Add clamp_t(u32, quantum, 256, 1<<20) after the zero reject and on the fallback path. The explicit-zero reject is preserved. Conditions to recreate the bug: CONFIG_NET_SCH_DRR=y. Requires CAP_NET_ADMIN (namespace-local via unshare -Urn suffices). tc qdisc add dev dummy0 root drr tc class add dev dummy0 parent 1: classid 1:1 drr quantum 1

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