net/sched: ets: clamp quantum in parse and fallback paths
ets_qdisc_change() falls back to psched_mtu() with no floor for bands
without an explicit quantum. With a crafted size table qdisc_pkt_len
reaches ~2 GiB, so a zero psched_mtu on a headerless device makes the
deficit-refill loop spin under the qdisc lock.
Move the floor into ets_quantum_parse() so explicitly configured quanta
are also clamped to [256, 1<<20], not just the fallback path.
Conditions to recreate the bug:
CONFIG_NET_SCH_ETS=y. Requires CAP_NET_ADMIN (namespace-local via
unshare -Urn suffices).
tc qdisc add dev dummy0 root ets bands 3 strict 2 quanta 1 1
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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No data.
No data.
No data available yet.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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Fri, 25 Sep 2026 10:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: net/sched: ets: clamp quantum in parse and fallback paths ets_qdisc_change() falls back to psched_mtu() with no floor for bands without an explicit quantum. With a crafted size table qdisc_pkt_len reaches ~2 GiB, so a zero psched_mtu on a headerless device makes the deficit-refill loop spin under the qdisc lock. Move the floor into ets_quantum_parse() so explicitly configured quanta are also clamped to [256, 1<<20], not just the fallback path. Conditions to recreate the bug: CONFIG_NET_SCH_ETS=y. Requires CAP_NET_ADMIN (namespace-local via unshare -Urn suffices). tc qdisc add dev dummy0 root ets bands 3 strict 2 quanta 1 1 | |
| Title | net/sched: ets: clamp quantum in parse and fallback paths | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-25T10:23:34.144Z
Reserved: 2026-09-25T10:19:56.068Z
Link: CVE-2026-98009
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-25T11:17:29.210
Modified: 2026-09-25T11:17:29.210
Link: CVE-2026-98009
Redhat
No data.
OpenCVE Enrichment
No data.
No weakness.