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.

CVSS

No CVSS.

References

Link	Resource
https://git.kernel.org/stable/c/0c66223e90ddb4fd3700965a9241f2fde7bd6bc7
https://git.kernel.org/stable/c/20b65bf7ca06e48ec1d62ed8012f71205328dbe4
https://git.kernel.org/stable/c/2164b512b97bb053e8ce4d6e95576f11bed6a005
https://git.kernel.org/stable/c/2446644b0f6d045b01db6acbaf55552dbec8a59a
https://git.kernel.org/stable/c/2e0f0729f922c8de13801004e2131b57646c7c5f
https://git.kernel.org/stable/c/99770b5d8e0e1c69b996f74a19d71afd2c4a9aa4
https://git.kernel.org/stable/c/dea2789a9d5ff38bdd77f2e64d550430899e2839
https://git.kernel.org/stable/c/fa9c2055f0a60f801ccf286af53d387dc6202c3f

Configurations

No configuration.

History

17 Sep 2026, 17:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-09-17 17:16

Updated : 2026-09-17 17:16

NVD link : CVE-2026-90073

Mitre link : CVE-2026-90073

CVE.ORG link : CVE-2026-90073

JSON object : View

Products Affected

No product.

CWE

No CWE.

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A device with a huge MTU (e.g. dummy with max_mtu == 0 accepting\nMTU 2147483634) makes weight * quantum overflow the signed deficit in\nhhf_dequeue(), spinning forever.\n\nClamp q->quantum before hhf_change() so both the opt and !opt paths see\na sane quantum. Without this, bare \"tc qdisc add ... hhf\" succeeds with\na clamped quantum but \"tc qdisc add ... hhf limit 1000\" (any option\npresent) fails with -EINVAL because hhf_change() re-validates the\nunclamped default (sch_hhf.c:559). 256 matches fq_codel's floor and is\na sane minimum for a DRR quantum.\n\nConditions to recreate the bug: a device whose MTU (plus\nhard_header_len) wraps psched_mtu() into the sign bit (e.g. a dummy\ndevice with max_mtu == 0 accepting MTU 2147483634). Requires\nCAP_NET_ADMIN in a user namespace."}], "lastModified": "2026-09-17T17:16:56.387", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}