net/sched: hhf: clamp quantum in change and init paths

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-98011
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-25 11:17:29 UTC
Updated2026-09-25 11:17:29 UTC
DescriptionIn 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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 10239edf86f137ce4c39b62ea9575e8053c549a0 1113b674307ffddd402524bd1fd9d7d5629b705b git Not specified
CNA Linux Linux affected 10239edf86f137ce4c39b62ea9575e8053c549a0 2e77947bbf6c166e76c038663832d0914418f761 git Not specified
CNA Linux Linux affected 10239edf86f137ce4c39b62ea9575e8053c549a0 0898c6f9fa9ce2632ae88bd0f34a878ccc6335af git Not specified
CNA Linux Linux affected 10239edf86f137ce4c39b62ea9575e8053c549a0 eb56a495f59baf6cad5ed80e3ffb9078098b1346 git Not specified
CNA Linux Linux affected 3.14 Not specified
CNA Linux Linux unaffected 3.14 semver Not specified
CNA Linux Linux unaffected 6.12.111 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.53 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.7 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc3 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/2e77947bbf6c166e76c038663832d0914418f761 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/1113b674307ffddd402524bd1fd9d7d5629b705b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/eb56a495f59baf6cad5ed80e3ffb9078098b1346 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/0898c6f9fa9ce2632ae88bd0f34a878ccc6335af 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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