Bug 2541140 (CVE-2026-98009) - CVE-2026-98009 kernel: net/sched: ets: clamp quantum in parse and fallback paths
Summary: CVE-2026-98009 kernel: net/sched: ets: clamp quantum in parse and fallback paths
Keywords:
Status: NEW
Alias: CVE-2026-98009
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-25 10:51 UTC by OSIDB Bzimport
Modified: 2026-09-28 19:54 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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Description OSIDB Bzimport 2026-09-25 10:51:47 UTC
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


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