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). 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
Affected versions
Linux kernel versions
5.10.239,
5.15.186,
6.1.129,
6.6.76,
6.12.13,
5.4.297,
6.13
and later are affected. Fixed in
5.10.271,
5.15.222,
6.1.189,
6.6.158,
6.12.111,
6.18.53,
7.2.7,
7.3-rc3
and their respective stable series.
References
8 totalFrequently asked questions
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What is CVE-2026-98012?
CVE-2026-98012 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 5.10.239 onward and has been patched in 5.10.271, 5.15.222, 6.1.189 and others. CVE-2026-98012 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-98012?
Yes. CVE-2026-98012 has been patched. Fixed versions include 5.10.271, 5.15.222, 6.1.189 and others. If you are running Linux kernel 5.10.239 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-98012 actively exploited?
No. CVE-2026-98012 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.