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CVE-2026-98009

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Last modified

CVE-2026-98009 is a vulnerability of currently unknown severity. 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.

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

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33, < 99ae477b892e203a37985ebc56f0063e072f7f4b; >= dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33, < 8f80b113dea0bed3c1a31a4224b72775cd9ec52d; >= dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33, < de22c30ec5598aca8797f02082d2ee1358dfa3ff; >= dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33, < 1c38487f46b243bfeefec0c0c86023a3904f2214
LinuxLinux5.6

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-98009?
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
How severe is CVE-2026-98009?
Severity scoring for CVE-2026-98009 is pending analysis.
How do I fix CVE-2026-98009?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST