{"id":"CVE-2026-90074","published":"2026-09-17T17:16:56.530","lastModified":"2026-09-17T17:16:56.530","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: fq_pie: clamp default quantum to avoid signed overflow\n\nfq_pie_init() sets q->quantum = psched_mtu(qdisc_dev(sch)) without\nclamping. A device with a huge MTU (e.g. dummy with max_mtu == 0\naccepting MTU 2147483634) makes psched_mtu() return 0x80000000, which\noverflows the signed flow->deficit to INT_MIN in fq_pie_qdisc_dequeue(),\ncausing an infinite loop and soft lockup. Emulate fq_pie_policy which\nis already bounded to [1, 1 << 20]; clamp the default to [256, 1 << 20].\n256 matches fq_codel's floor and is a sane minimum for a DRR quantum.\n\nConditions to recreate the bug: a device whose MTU (plus\nhard_header_len) wraps psched_mtu() into the sign bit (e.g. a dummy\ndevice with max_mtu == 0 accepting MTU 2147483634). Requires\nCAP_NET_ADMIN in a user namespace.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/044fa2498bbc2900f0c48a6ef2fdd5b2bdfc3795","tags":[]},{"url":"https://git.kernel.org/stable/c/1f43e4dbc93b7d02761a024d5f895df823c07b72","tags":[]},{"url":"https://git.kernel.org/stable/c/435da3734a8e63d3067016accc977ed1d10aaaa0","tags":[]},{"url":"https://git.kernel.org/stable/c/44dad8fe99b58a7fe2961e9eec6a5f07ace5b51f","tags":[]},{"url":"https://git.kernel.org/stable/c/6f1be05faecef4c0f9a008200209f66ef2e133f7","tags":[]},{"url":"https://git.kernel.org/stable/c/bf97fd2163ad1191ef8daa3d4df8372aee19e396","tags":[]},{"url":"https://git.kernel.org/stable/c/c86cd7ed0b0e44779a3d1683f03e4353baf4bdc9","tags":[]},{"url":"https://git.kernel.org/stable/c/f7942b2693bc24c7d609a03d06f97bee3b0bd96a","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}