{"id":"CVE-2026-90072","revision":"f41cb79eb2b04583a756674130cc80d4","records":[{"revision":"f41cb79eb2b04583a756674130cc80d4","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-90072","aliases":[],"title":"net/sched: sfq: clamp quantum to avoid signed overflow soft lockup","description":"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. 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.","state":0,"publishedAt":"2026-09-17T16:05:52.905+00:00","modifiedAt":"2026-10-19T08:57:29.264+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"unaffected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/sched/sch_sfq.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"86799499585af06a9431c9e7782658667bd62650\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"2017c355a5a1af77736cd1739fe922f69b5652dc\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"6581a82bf08ba5d4e2a6d4e3080df43315b296c4\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"9d782c662879c3adaaca30e05c36910ad11b9e54\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"d72dbdfaeb5b9b8d884e0e036c3442754379ef74\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"aeb8196ecb95146e3410f635628e6cd47352b3e5\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"da16c31517cd2c06bb2c78c73e91ae192c01c426\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        },\n                        {\n                            \"version\": \"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2\",\n                            \"lessThan\": \"816e90057ab1879562a5b7cc688e35bb9027ae97\",\n                            \"status\": \"affected\",\n                            \"versionType\": \"git\"\n                        }\n                    ]\n                }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"product\": \"Linux\",\n                    \"vendor\": \"Linux\",\n                    \"defaultStatus\": \"affected\",\n                    \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n                    \"programFiles\": [\n                        \"net/sched/sch_sfq.c\"\n                    ],\n                    \"versions\": [\n                        {\n                            \"version\": \"2.6.12\",\n                            \"status\": \"affected\"\n                        },\n                        {\n                            \"version\": \"0\",\n                            \"lessThan\": \"2.6.12\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.10.270\",\n                            \"lessThanOrEqual\": \"5.10.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"5.15.221\",\n                            \"lessThanOrEqual\": \"5.15.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.1.188\",\n                            \"lessThanOrEqual\": \"6.1.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.6.157\",\n                            \"lessThanOrEqual\": \"6.6.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.12.110\",\n                            \"lessThanOrEqual\": \"6.12.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"6.18.52\",\n                            \"lessThanOrEqual\": \"6.18.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.2.6\",\n                            \"lessThanOrEqual\": \"7.2.*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"semver\"\n                        },\n                        {\n                            \"version\": \"7.3\",\n                            \"lessThanOrEqual\": \"*\",\n                            \"status\": \"unaffected\",\n                            \"versionType\": \"original_commit_for_fix\"\n                        }\n                    ]\n                }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/86799499585af06a9431c9e7782658667bd62650","https://git.kernel.org/stable/c/2017c355a5a1af77736cd1739fe922f69b5652dc","https://git.kernel.org/stable/c/6581a82bf08ba5d4e2a6d4e3080df43315b296c4","https://git.kernel.org/stable/c/9d782c662879c3adaaca30e05c36910ad11b9e54","https://git.kernel.org/stable/c/d72dbdfaeb5b9b8d884e0e036c3442754379ef74","https://git.kernel.org/stable/c/aeb8196ecb95146e3410f635628e6cd47352b3e5","https://git.kernel.org/stable/c/da16c31517cd2c06bb2c78c73e91ae192c01c426","https://git.kernel.org/stable/c/816e90057ab1879562a5b7cc688e35bb9027ae97"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-90072","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-90072","identifiers":["CVE-2026-90072"]},"retained":false,"historicalAffected":[]}],"coverage":[]}