CVE-2026-98012
In the Linux kernel, the following vulnerability has been resolved:
net/sched: sfq: clamp quantum in change path
sfq_change() accepts any non-negative quantum (only rejects (int)ctl->quantum < 0). 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, ...) matching fq_codel_change(). Reject quantum > 1<<20 with -EINVAL, matching fq_codel_change() and the init clamp.
Detalles técnicos trazas, registros y código del informe original
Conditions to recreate the bug: CONFIG_NET_SCH_SFQ=y. Requires CAP_NET_ADMIN (namespace-local via unshare -Urn suffices). tc qdisc add dev dummy0 root sfq tc qdisc change dev dummy0 root sfq quantum 1 stab data 32768 size_log 15 cell_log 0
CVSS
NVD no ha asignado puntuación CVSS a esta CVE (habitual desde el cambio de política de abril de 2026).
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.18%
- Percentil entre todas las CVEs puntuadas: 7
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
Referencias
- https://git.kernel.org/stable/c/0692ce5a528df450d64e9f819054177e9d91076f
- https://git.kernel.org/stable/c/4117c528b2de5fdc3e4a7e3626815b616a635cdc
- https://git.kernel.org/stable/c/534cd7ecbbc6e8a974f4003a5c1557439c6e0a72
- https://git.kernel.org/stable/c/e4192bcf83aaab02129644ddf4656fd86e93751f
- https://git.kernel.org/stable/c/e6c1cb728e389354203a72bc77464c222a247aeb
- https://git.kernel.org/stable/c/f3820dce042a673fcb28cc31c87ee14257e21a17
- https://git.kernel.org/stable/c/f82fa6f10d4a69322cad0f7a4aa523ce6292a5a0
- https://git.kernel.org/stable/c/fb9f88a33c516ea5c0bcd9a22ca288b246b34567
JSON original (NVD)
Mostrar
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"published": "2026-09-25T11:17:29.537",
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}
],
"vulnStatus": "Received",
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sfq: clamp quantum in change path\n\nsfq_change() accepts any non-negative quantum (only rejects\n(int)ctl->quantum < 0). With a crafted size table qdisc_pkt_len reaches\n~2 GiB, so quantum=1 makes the deficit-refill loop spin ~2^31 times\nunder the qdisc lock (a soft lockup / denial of service).\n\nAdd max(256U, ...) matching fq_codel_change(). Reject quantum > 1<<20\nwith -EINVAL, matching fq_codel_change() and the init clamp.\n\nConditions to recreate the bug:\n CONFIG_NET_SCH_SFQ=y. Requires CAP_NET_ADMIN (namespace-local via\n unshare -Urn suffices).\n\n tc qdisc add dev dummy0 root sfq\n tc qdisc change dev dummy0 root sfq quantum 1 stab data 32768 size_log 15 cell_log 0"
}
],
"lastModified": "2026-10-03T11:18:24.263",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}