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CVE.org (no NVD analysis yet)· CNA Linux

CVE-2026-98234: net/sched: hhf: cap hh_flows_limit at change time

—No exploit Fix available

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: 0.17% (FIRST EPSS).
  • Fixed version: Linux Linux 06d2a101e89063cb0b9b459104db48bdfb0a797d, 1731ff1d20489afe4cd01b7d16d37f324746ac54, 2cef2588c995722a901368def30befeef9ae55c6; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.158.1-1.

Low priority for now. Upgrade to Linux Linux 06d2a101e89063cb0b9b459104db48bdfb0a797d, 1731ff1d20489afe4cd01b7d16d37f324746ac54, 2cef2588c995722a901368def30befeef9ae55c6; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.158.1-1 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: cap hh_flows_limit at change time hhf_change() stores TCA_HHF_HH_FLOWS_LIMIT with no upper bound. A huge hh_flows_limit lets each new heavy-hitter flow pass the hh_flows_current_cnt check in alloc_new_hh() and forces a fixed-size kzalloc(GFP_ATOMIC) per flow under spoofed traffic, for unbounded memory growth. Bound the attribute with NLA_POLICY_MAX() at 2*HH_FLOWS_CNT (the hhf_init() default) and report the rejected value via extack. The deprecated nested parse is kept: legacy tc does not set NLA_F_NESTED on TCA_OPTIONS. Configs relying on hh_limit above the default were relying on unbounded, unsafe behaviour and are not supported going forward. hhf_init() also ran hhf_change() before setting the default hh_flows_limit, so a user-supplied hh_limit at add time was clobbered back to 2048. Set the default before hhf_change() so the configured value sticks. This is a follow-up to commit eb56a495f59b ("net/sched: hhf: clamp quantum in change and init paths"), which bounded the quantum of the same qdisc; the hh_flows_limit bound is the remaining unbounded knob of that series' scope. Conditions to recreate the bug: CAP_NET_ADMIN in a user namespace; tc qdisc change dev X root hhf hh_limit 4294967295 succeeds and the value is echoed by tc qdisc show, unbounding heavy-hitter flow allocations; also tc qdisc add dev X root hhf hh_limit 500 stores 2048 instead of 500.

Published
Oct 6, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 7th 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 · 0.1%

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Noroxi analysis

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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 7adfd0a42174b85c6bd678858ecd6674f403f336affected · git
    • 10239edf86f137ce4c39b62ea9575e8053c549a0 and later · before 35fd423a5c5132c6f4321f6c4f0a7b4b90af830caffected · git
    • 10239edf86f137ce4c39b62ea9575e8053c549a0 and later · before 06d2a101e89063cb0b9b459104db48bdfb0a797daffected · git
    • 10239edf86f137ce4c39b62ea9575e8053c549a0 and later · before d8e2f1f0263b7c97b222c06070cccf13e0ab7112affected · git
    • 10239edf86f137ce4c39b62ea9575e8053c549a0 and later · before f3f4a5cb4a6e9b1f1f25d34dfc25f836a1601db4affected · git
    • 10239edf86f137ce4c39b62ea9575e8053c549a0 and later · before 1731ff1d20489afe4cd01b7d16d37f324746ac54affected · git
    • 10239edf86f137ce4c39b62ea9575e8053c549a0 and later · before f6547d27ce2093c5627636fb63dd0b7523c466f9affected · git
    • 10239edf86f137ce4c39b62ea9575e8053c549a0 and later · before 2cef2588c995722a901368def30befeef9ae55c6affected · 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 6.12.113-1~deb12u16.12.113-1~deb12u1
Debian:13linuxbefore 6.12.113-16.12.113-1
Debian:14linuxbefore 7.2.8-17.2.8-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

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    40Plan
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    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-98232Oct 6, 2026 · scsi: core: Validate MODE SENSE lengths in scsi_cdl_enable()
    0Monitor
  • ← EarlierCVE-2026-98233Oct 6, 2026 · net/packet: clear RX owner on VNET header error
    0Monitor
  • Later →CVE-2026-98235Oct 6, 2026 · net/sched: act_api: release tail references on DELACTION failure
    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 Linux06d2a101e89063cb0b9b459104db48bdfb0a797dVendor (CNA)
Linux Linux1731ff1d20489afe4cd01b7d16d37f324746ac54Vendor (CNA)
Linux Linux2cef2588c995722a901368def30befeef9ae55c6Vendor (CNA)
Linux Linux35fd423a5c5132c6f4321f6c4f0a7b4b90af830cVendor (CNA)
Linux Linux7adfd0a42174b85c6bd678858ecd6674f403f336Vendor (CNA)
Linux Linuxd8e2f1f0263b7c97b222c06070cccf13e0ab7112Vendor (CNA)
Linux Linuxf3f4a5cb4a6e9b1f1f25d34dfc25f836a1601db4Vendor (CNA)
Linux Linuxf6547d27ce2093c5627636fb63dd0b7523c466f9Vendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.06.6.158.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux6.12.113-1 · Debian:13Package registry (OSV)
debian:linux7.2.8-1 · Debian:14Package registry (OSV)
debian:linux-6.126.12.113-1~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.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 12, 2026+38 d
EPSS, last 120 days

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

Not on record for this CVE: patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

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.

References

Show all references (7 more)

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

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