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CVE-2026-98012

In the Linux kernel, the following vulnerability has been resolved: net/sched: sfq: clamp quantum in change path sfq_change() accepts any non-negative quantum (only rejects (int)ctl->quantum < 0).

Published Sep 25, 2026EPSS 0.18%

Overview

CVE-2026-98012 is a known-severity vulnerability. It was published on September 25, 2026.

Technical description

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

net/sched: sfq: clamp quantum in change path

sfq_change() accepts any non-negative quantum (only rejects

(int)ctl->quantum < 0). 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(). Reject quantum > 1<<20

with -EINVAL, matching fq_codel_change() and the init clamp.

Conditions to recreate the bug:

CONFIG_NET_SCH_SFQ=y. Requires CAP_NET_ADMIN (namespace-local via

unshare -Urn suffices).

tc qdisc add dev dummy0 root sfq

tc qdisc change dev dummy0 root sfq quantum 1 stab data 32768 size_log 15 cell_log 0

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.

Frequently asked questions

What is CVE-2026-98012?

CVE-2026-98012 is a known-severity vulnerability. It was published on September 25, 2026.

How severe is CVE-2026-98012?

CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.

How do I fix or remediate CVE-2026-98012?

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.

How can CyberStrike help with CVE-2026-98012?

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