CVE-2026-90073
Received
Received - Intake
BaseFortify
Vulnerability report for CVE-2026-90073, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-09-17
Last updated on: 2026-09-17
Assigner: kernel.org
Description
Description
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 Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
Currently, no data is known.
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
