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NVD / CVE Program· CNA Linux

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

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.21% (FIRST EPSS).
  • Fixed version: Linux Linux 0c66223e90ddb4fd3700965a9241f2fde7bd6bc7, 20b65bf7ca06e48ec1d62ed8012f71205328dbe4, 2164b512b97bb053e8ce4d6e95576f11bed6a005; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1.

Low priority for now. Upgrade to Linux Linux 0c66223e90ddb4fd3700965a9241f2fde7bd6bc7, 20b65bf7ca06e48ec1d62ed8012f71205328dbe4, 2164b512b97bb053e8ce4d6e95576f11bed6a005; azl3 kernel 6.6.152.1-1 on Azure Linux 3.0 6.6.157.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

—No exploit Fix available
Published
Sep 17, 2026
Updated
Oct 19, 2026
EPSS
0.2% · 12th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

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  • A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 3.14affected
    • 10239edf86f137ce4c39b62ea9575e8053c549a0 and later · before 2e0f0729f922c8de13801004e2131b57646c7c5faffected · git
    • 10239edf86f137ce4c39b62ea9575e8053c549a0 and later · before 0c66223e90ddb4fd3700965a9241f2fde7bd6bc7affected · git
    • 10239edf86f137ce4c39b62ea9575e8053c549a0 and later · before 20b65bf7ca06e48ec1d62ed8012f71205328dbe4affected · git
    • 10239edf86f137ce4c39b62ea9575e8053c549a0 and later · before dea2789a9d5ff38bdd77f2e64d550430899e2839affected · git
    • 10239edf86f137ce4c39b62ea9575e8053c549a0 and later · before fa9c2055f0a60f801ccf286af53d387dc6202c3faffected · git
    • 10239edf86f137ce4c39b62ea9575e8053c549a0 and later · before 99770b5d8e0e1c69b996f74a19d71afd2c4a9aa4affected · git
    • 10239edf86f137ce4c39b62ea9575e8053c549a0 and later · before 2446644b0f6d045b01db6acbaf55552dbec8a59aaffected · git
    • 10239edf86f137ce4c39b62ea9575e8053c549a0 and later · before 2164b512b97bb053e8ce4d6e95576f11bed6a005affected · git
    • before 3.14not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
Debian:14linuxbefore 7.2.6-17.2.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-90071Sep 17, 2026 · net/sched: sch_teql: restore skb->dev on the slave failure path
    31Monitor
  • ← EarlierCVE-2026-90072Sep 17, 2026 · net/sched: sfq: clamp quantum to avoid signed overflow soft lockup
    0Monitor
  • Later →CVE-2026-90074Sep 17, 2026 · net/sched: fq_pie: clamp default quantum to avoid signed overflow
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux0c66223e90ddb4fd3700965a9241f2fde7bd6bc7Vendor (CNA)
Linux Linux20b65bf7ca06e48ec1d62ed8012f71205328dbe4Vendor (CNA)
Linux Linux2164b512b97bb053e8ce4d6e95576f11bed6a005Vendor (CNA)
Linux Linux2446644b0f6d045b01db6acbaf55552dbec8a59aVendor (CNA)
Linux Linux2e0f0729f922c8de13801004e2131b57646c7c5fVendor (CNA)
Linux Linux99770b5d8e0e1c69b996f74a19d71afd2c4a9aa4Vendor (CNA)
Linux Linuxdea2789a9d5ff38bdd77f2e64d550430899e2839Vendor (CNA)
Linux Linuxfa9c2055f0a60f801ccf286af53d387dc6202c3fVendor (CNA)
azl3 kernel 6.6.150.1-1 on Azure Linux 3.0—Microsoft (MSRC)
azl3 kernel 6.6.152.1-1 on Azure Linux 3.06.6.157.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux6.12.111-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.111-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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