Linux Kernel up to 6.12.110/6.18.52/7.2.6/7.3-rc2 hhf net/sched hhf_change/hhf_init quantum denial of service

CVSS Meta Temp Score
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CTI Interest Score
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4.2$0-$5k0.00+

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.12.110/6.18.52/7.2.6/7.3-rc2. It has been rated as problematic. This affects the function hhf_change/hhf_init of the file net/sched of the component hhf. The manipulation of the argument quantum leads to denial of service. This vulnerability is documented as CVE-2026-98011. The attack needs to be performed locally. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.12.110/6.18.52/7.2.6/7.3-rc2. It has been rated as problematic. This issue affects the function hhf_change/hhf_init of the file net/sched of the component hhf. The manipulation of the argument quantum with an unknown input leads to a denial of service vulnerability. Using CWE to declare the problem leads to CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. Impacted is availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: net/sched: hhf: clamp quantum in change and init paths hhf_change() accepts any quantum from userspace, including 1. With a crafted size table qdisc_pkt_len reaches ~2 GiB, so quantum=1 makes the deficit-refill loop spin ~2^31 times under the qdisc lock (a soft lockup / denial of service). Add max(256U, ...) in hhf_change() matching fq_codel_change(). Clamp hhf_init() to [256, 1<<20] matching the siblings, and remove the old fallback that only set quantum=256 on overflow. Conditions to recreate the bug: CONFIG_NET_SCH_HHF=y. Requires CAP_NET_ADMIN (namespace-local via unshare -Urn suffices). tc qdisc add dev dummy0 root hhf tc qdisc change dev dummy0 root hhf quantum 1 stab data 32768 size_log 15 cell_log 0

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2026-98011 since 09/25/2026. The exploitation is known to be easy. Attacking locally is a requirement. The exploitation needs additional levels of successful authentication. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 6.12.111, 6.18.53, 7.2.7 or 7.3-rc3 eliminates this vulnerability. Applying the patch 1113b674307ffddd402524bd1fd9d7d5629b705b/2e77947bbf6c166e76c038663832d0914418f761/0898c6f9fa9ce2632ae88bd0f34a878ccc6335af/eb56a495f59baf6cad5ed80e3ffb9078098b1346 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.4
VulDB Meta Temp Score: 4.2

VulDB Base Score: 4.4
VulDB Temp Score: 4.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Denial of service
CWE: CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.12.111/6.18.53/7.2.7/7.3-rc3
Patch: 1113b674307ffddd402524bd1fd9d7d5629b705b/2e77947bbf6c166e76c038663832d0914418f761/0898c6f9fa9ce2632ae88bd0f34a878ccc6335af/eb56a495f59baf6cad5ed80e3ffb9078098b1346

Timelineinfo

09/25/2026 Advisory disclosed
09/25/2026 +0 days CVE reserved
09/25/2026 +0 days VulDB entry created
09/25/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-98011 (🔒)
GCVE (CVE): GCVE-0-2026-98011
GCVE (VulDB): GCVE-100-410291

Entryinfo

Created: 09/25/2026 16:29
Changes: 09/25/2026 16:29 (61)
Complete: 🔍
Cache ID: 216::103

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