CVEvulnerability
CVE-2026-98009
- Status
- Received
- Published
- 2026-09-25
- Last modified
- 2026-10-19
- Assigner
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
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
References
- https://git.kernel.org/stable/c/1c38487f46b243bfeefec0c0c86023a3904f2214 git.kernel.org
- https://git.kernel.org/stable/c/226d2702e74a570f5bfae6115b4706da4b94e5cf git.kernel.org
- https://git.kernel.org/stable/c/440b66cc7b56ea38e9b878ae88da91992efaa4c4 git.kernel.org
- https://git.kernel.org/stable/c/4ef8664eafafc8db68a1d52601f17dc008a223b7 git.kernel.org
- https://git.kernel.org/stable/c/8b8d782c3b96376217087767dcf662cd3d25f226 git.kernel.org
- https://git.kernel.org/stable/c/8f80b113dea0bed3c1a31a4224b72775cd9ec52d git.kernel.org
- https://git.kernel.org/stable/c/99ae477b892e203a37985ebc56f0063e072f7f4b git.kernel.org
- https://git.kernel.org/stable/c/de22c30ec5598aca8797f02082d2ee1358dfa3ff git.kernel.org