net/sched: hhf: clamp quantum before hhf_change() to avoid overflow
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 2 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) 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
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
Not affected: 6 products
- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
- Red Hat OpenShift Container Platform 5
Timeline
- 2026-10-02 Threatist record created from CVE-2026-90073
- 2026-10-03 Alias added: GHSA-xxq9-2g6r-mm98
- 2026-10-13 Affected versions changed · Red Hat
- 2026-10-13 CVSS score added · Red Hat
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-11-06 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/2e0f0729f922c8de13801004e2131b57646c7c5f
- https://git.kernel.org/stable/c/0c66223e90ddb4fd3700965a9241f2fde7bd6bc7
- https://git.kernel.org/stable/c/20b65bf7ca06e48ec1d62ed8012f71205328dbe4
- https://git.kernel.org/stable/c/dea2789a9d5ff38bdd77f2e64d550430899e2839
- https://git.kernel.org/stable/c/fa9c2055f0a60f801ccf286af53d387dc6202c3f
- https://git.kernel.org/stable/c/99770b5d8e0e1c69b996f74a19d71afd2c4a9aa4
- https://git.kernel.org/stable/c/2446644b0f6d045b01db6acbaf55552dbec8a59a
- https://git.kernel.org/stable/c/2164b512b97bb053e8ce4d6e95576f11bed6a005
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Sources
- CVE-2026-90073 · CVE Program
- CVE-2026-90073 · NVD
- FIRST EPSS
- GHSA-xxq9-2g6r-mm98 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-90073 · Red Hat security data · CC BY 4.0
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