{"id":"AZL-102920","summary":"CVE-2026-90072 affecting package kernel 6.6.150.1-1","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sfq: clamp quantum to avoid signed overflow soft lockup\n\nsfq_init() sets q-\u003equantum = psched_mtu(qdisc_dev(sch)) (unsigned). A\ndevice with a huge MTU (e.g. dummy with max_mtu == 0 accepting MTU\n2147483634) makes psched_mtu() return 0x80000000, so slot-\u003eallot = INT_MIN\nand INT_MIN + INT_MIN toggles between INT_MIN and 0 forever, spinning\nsfq_dequeue() under the qdisc lock.\n\nClamp the quantum to [256, 1 \u003c\u003c 20] so the refill loop terminates. The\nlower bound also covers q-\u003equantum == 0 (psched_mtu() returning 0),\nwhich spins sfq_dequeue() identically. sfq_change() already rejects a\nnegative quantum, so only the init path was exposed.\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.","modified":"2026-09-18T14:18:02.857695096Z","published":"2026-09-17T17:16:56Z","upstream":["CVE-2026-90072"],"references":[{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90072"}],"affected":[{"package":{"name":"kernel","ecosystem":"Azure Linux:3","purl":"pkg:rpm/azure-linux/kernel"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"6.6.150.1-1"}]}],"database_specific":{"source":"https://github.com/microsoft/AzureLinuxVulnerabilityData/blob/main/osv/AZL-102920.json"}}],"schema_version":"1.9.0"}