Unknown

CVE-2026-90073 — net/sched: hhf: clamp quantum before hhf_change() to avoid overflow

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.

Published Sep 17, 2026 · Updated Oct 19, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.2% (30-day exploitation probability)+2

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.21%

ahead of 11% of scored CVEs · Oct 19, 2026

Affects

Linux

CVSS base

—

Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ 10239edf86f137ce4c39b62ea9575e8053c549a0 and < 2e0f0729f922c8de13801004e2131b57646c7c5f≥ 10239edf86f137ce4c39b62ea9575e8053c549a0 and < 0c66223e90ddb4fd3700965a9241f2fde7bd6bc7≥ 10239edf86f137ce4c39b62ea9575e8053c549a0 and < 20b65bf7ca06e48ec1d62ed8012f71205328dbe4≥ 10239edf86f137ce4c39b62ea9575e8053c549a0 and < dea2789a9d5ff38bdd77f2e64d550430899e2839≥ 10239edf86f137ce4c39b62ea9575e8053c549a0 and < fa9c2055f0a60f801ccf286af53d387dc6202c3f≥ 10239edf86f137ce4c39b62ea9575e8053c549a0 and < 99770b5d8e0e1c69b996f74a19d71afd2c4a9aa4≥ 10239edf86f137ce4c39b62ea9575e8053c549a0 and < 2446644b0f6d045b01db6acbaf55552dbec8a59a≥ 10239edf86f137ce4c39b62ea9575e8053c549a0 and < 2164b512b97bb053e8ce4d6e95576f11bed6a005 and 1 more version 3.14	Vulnerable	CVE Program (cve.org) e CISA ADP

EPSS over time FIRST

Oct 15, 2026 → Oct 19, 2026 · 4 reading(s) · max 0.21%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Not enough vector or weakness data: use the affected application’s logs as a starting point.

application logs

Timeline

What happened to this CVE, newest first.

2026
Record published
Oct 15, 2026
Affected products added · linux/linux
Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
Source status changed · → Received
Oct 15, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 15, 2026 · NIST National Vulnerability Database
CVE published
Sep 17, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

1× References added · Oct 19, 2026 – Oct 19, 2026
1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

10 on the record

git.kernel.org/stable/c/99770b5d8e0e1c69b996f74a19d71afd2c4a9aa4
NIST National Vulnerability Database
git.kernel.org/stable/c/0c66223e90ddb4fd3700965a9241f2fde7bd6bc7
NIST National Vulnerability Database
git.kernel.org/stable/c/fa9c2055f0a60f801ccf286af53d387dc6202c3f
NIST National Vulnerability Database
github.com/advisories/GHSA-xxq9-2g6r-mm98
GitHub Security Advisories
git.kernel.org/stable/c/20b65bf7ca06e48ec1d62ed8012f71205328dbe4
NIST National Vulnerability Database
git.kernel.org/stable/c/2164b512b97bb053e8ce4d6e95576f11bed6a005
NIST National Vulnerability Database
nvd.nist.gov/vuln/detail/CVE-2026-90073
GitHub Security Advisories
git.kernel.org/stable/c/dea2789a9d5ff38bdd77f2e64d550430899e2839
NIST National Vulnerability Database
git.kernel.org/stable/c/2446644b0f6d045b01db6acbaf55552dbec8a59a
NIST National Vulnerability Database
git.kernel.org/stable/c/2e0f0729f922c8de13801004e2131b57646c7c5f
NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Unknown CVE-2026-98866 sched/cache: Introduce task_struct->sched_cache_grp to fix UAF 1d
Unknown CVE-2026-98867 dm-pcache: bound the logical key offset from persistent memory 1d
Unknown CVE-2026-98868 dm-pcache: reject a kset that overruns its segment 1d
Unknown CVE-2026-98856 kprobes: Skip disarmed probes when checking optkprobe overlap 1d
Unknown CVE-2026-98857 ipvs: bound LBLCR and LBLC cache growth 1d
Unknown CVE-2026-98858 io_uring: fix task_work add use-after-free with SQPOLL 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No CVSS score published by NVD, the CNA, CISA or GitHub so far.
No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-90073 is "net/sched: hhf: clamp quantum before hhf_change() to avoid overflow", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.21% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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