{"id":"CVE-2026-90072","title":"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->quantum = psched_mtu(qdisc_dev(sch)) (unsigned)","summary":"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->quantum = psched_mtu(qdisc_dev(sch)) (unsigned). A\ndevice with a huge MTU (e.g. d…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 86799499585af06a9431c9e7782658667bd62650","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 2017c355a5a1af77736cd1739fe922f69b5652dc","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 6581a82bf08ba5d4e2a6d4e3080df43315b296c4","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 9d782c662879c3adaaca30e05c36910ad11b9e54","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < d72dbdfaeb5b9b8d884e0e036c3442754379ef74","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < aeb8196ecb95146e3410f635628e6cd47352b3e5","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < da16c31517cd2c06bb2c78c73e91ae192c01c426","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 816e90057ab1879562a5b7cc688e35bb9027ae97","Linux 2.6.12"],"published":"2026-09-17","updated":"2026-09-17","sourceUpdated":"2026-09-17T17:16:56.250","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-90072","references":[{"url":"https://git.kernel.org/stable/c/2017c355a5a1af77736cd1739fe922f69b5652dc","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6581a82bf08ba5d4e2a6d4e3080df43315b296c4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/816e90057ab1879562a5b7cc688e35bb9027ae97","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/86799499585af06a9431c9e7782658667bd62650","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9d782c662879c3adaaca30e05c36910ad11b9e54","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/aeb8196ecb95146e3410f635628e6cd47352b3e5","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d72dbdfaeb5b9b8d884e0e036c3442754379ef74","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/da16c31517cd2c06bb2c78c73e91ae192c01c426","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-17T16:21:47.897Z","epss":0.0021,"epssPercentile":0.11548,"slug":"CVE-2026-90072","body":"## Overview\n\nIn 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->quantum = 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->allot = 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 << 20] so the refill loop terminates. The\nlower bound also covers q->quantum == 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}