{"id":"CVE-2026-98012","published":"2026-09-25T11:17:29.537","lastModified":"2026-09-25T11:17:29.537","description":"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","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/534cd7ecbbc6e8a974f4003a5c1557439c6e0a72","tags":[]},{"url":"https://git.kernel.org/stable/c/e6c1cb728e389354203a72bc77464c222a247aeb","tags":[]},{"url":"https://git.kernel.org/stable/c/f3820dce042a673fcb28cc31c87ee14257e21a17","tags":[]},{"url":"https://git.kernel.org/stable/c/fb9f88a33c516ea5c0bcd9a22ca288b246b34567","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}