AZL-104574

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Import Source
https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-104574.json
JSON Data
https://api.osv.dev/v1/vulns/AZL-104574
Upstream
Published
2026-09-25T11:17:29Z
Modified
2026-09-29T05:37:47Z
Summary
CVE-2026-98011 affecting package kernel 6.6.157.1-1
Details

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

References

Affected packages

Azure Linux:3 / kernel

Package

Name
kernel
Purl
pkg:rpm/azure-linux/kernel

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Last Affected
6.6.157.1-1

Database specific

source
"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-104574.json"