CVE-2026-90073
In the Linux kernel, the following vulnerability has been resolved: net/sched: hhf: clamp quantum before hhf_change() to avoid overflow hhf_init() sets q->quantum = psched_mtu(qdisc_dev(sch)) with no overflow check. A device with a huge MTU (e.g. dummy with max_mtu == 0 accepting MTU 2147483634) makes weight * quantum overflow the signed deficit in hhf_dequeue(), spinning forever. Clamp q->quantum before hhf_change() so both the opt and !opt paths see a sane quantum. Without this, bare "tc qdisc add ... hhf" succeeds with a clamped quantum but "tc qdisc add ... hhf limit 1000" (any option present) fails with -EINVAL because hhf_change() re-validates the unclamped default (sch_hhf.c:559). 256 matches fq_codel's floor and is a sane minimum for a DRR quantum. Conditions to recreate the bug: a device whose MTU (plus hard_header_len) wraps psched_mtu() into the sign bit (e.g. a dummy device with max_mtu == 0 accepting MTU 2147483634). Requires CAP_NET_ADMIN in a user namespace.
Affected versions
Linux kernel versions
3.14
and later are affected. Fixed in
5.10.270,
5.15.221,
6.1.188,
6.6.157,
6.12.110,
6.18.52,
7.2.6,
7.3-rc1
and their respective stable series.
References
8 totalFrequently asked questions
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What is CVE-2026-90073?
CVE-2026-90073 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 3.14 onward and has been patched in 5.10.270, 5.15.221, 6.1.188 and others. CVE-2026-90073 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-2026-90073?
Yes. CVE-2026-90073 has been patched. Fixed versions include 5.10.270, 5.15.221, 6.1.188 and others. If you are running Linux kernel 3.14 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-90073 actively exploited?
No. CVE-2026-90073 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.