Local denial of service via undersized HHF quantum
Published Sep 25, 2026 · Updated Sep 25, 2026
Denial of service in the Linux HHF qdisc allows local users to cause a soft lockup through a crafted traffic-control configuration. hhf_change() accepts a quantum of 1, so an inflated qdisc packet length drives excessive deficit-refill iterations while the qdisc lock is held. Reachability requires CONFIG_NET_SCH_HHF and namespace-local CAP_NET_ADMIN, and unshare -Urn suffices to satisfy the privilege gate.
Summary
What happened
Denial of service in the Linux HHF qdisc allows local users to cause a soft lockup through a crafted traffic-control configuration. hhf_change() accepts a quantum of 1, so an inflated qdisc packet length drives excessive deficit-refill iterations while the qdisc lock is held. Reachability requires CONFIG_NET_SCH_HHF and namespace-local CAP_NET_ADMIN, and unshare -Urn suffices to satisfy the privilege gate.
The record
- CVE
- CVE-2026-98011
- Published
- Sep 25, 2026
- Updated
- Sep 25, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 25, 2026CVE publishedPublication date reported by the CVE source.
- Sep 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=10239edf86f137ce4c39b62ea9575e8053c549a0 <0898c6f9fa9ce2632ae88bd0f34a878ccc6335af
- Affected versionversion=10239edf86f137ce4c39b62ea9575e8053c549a0 <1113b674307ffddd402524bd1fd9d7d5629b705b
- Affected versionversion=10239edf86f137ce4c39b62ea9575e8053c549a0 <2e77947bbf6c166e76c038663832d0914418f761
- Affected versionversion=10239edf86f137ce4c39b62ea9575e8053c549a0 <eb56a495f59baf6cad5ed80e3ffb9078098b1346
- Affected versionversion=3.14
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
- Upstream HHF soft-lockup reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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