CVE-2026-93182
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: sched/fair: Fix overflow in update_tg_cfs_runnable() A divide-by-zero crash is observed when running hackbench: [14697.488452] CPU: 112 UID: 0 PID: 124791 Comm: hackbench Not tainted 7.1.0-rc2+ [14697.492627] RIP: 0010:propagate_entity_load_avg+0x35f/0x3e0 [14697.506799] <TASK> [14697.507411] __dequeue_task+0x2b4/0xc70 [14697.508677] dequeue_task_fair+0x36/0x370 [14697.509047] dequeue_task+0x101/0x2f0 [14697.509426] __schedule+0x1b1/0x1a00 [14697.510868] anon_pipe_read+0x3da/0x450 [14697.511400] vfs_read+0x361/0x390 [14697.512053] __x64_sys_read+0x19/0x30 The divide-by-zero happens here: if (scale_load_down(gcfs_rq->load.weight)) { load_sum = div_u64(gcfs_rq->avg.load_sum, scale_load_down(gcfs_rq->load.weight)); } gcfs_rq->load.weight is an insane large value and is truncated to the lower 32 bits by div_u64, which happen to be 0. Using AI for investigation, the cause is a u32 overflow in update_tg_cfs_runnable(), and flat pickup became a victim when using tg_tasks(): u32 new_sum, divider; ... new_sum = se->avg.runnable_avg * divider; <-- boom The following sequence shows how this triggers the crash: propagate_entity_load_avg() update_tg_cfs_runnable() # u32 overflow corrupts runnable_sum __update_load_avg_cfs_rq() ___update_load_avg() # computes insane runnable_avg update_tg_load_avg() # propagates to tg->runnable_avg update_cfs_group() calc_concur_shares() tg_tasks() # long-to-int truncation, negative nr reweight_entity() # corrupted se->load.weight update_load_add() # corrupted cfs_rq->load.weight propagate_entity_load_avg() update_tg_cfs_load() div_u64() # divide-by-zero Fix by widening new_sum from u32 to u64 (no need to force tg_tasks() to return unsigned long after this fix)
View original CVE JSON
{
"id": "CVE-2026-93182",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-09-17T17:18:14.153",
"lastModified": "2026-10-19T10:17:08.693",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched/fair: Fix overflow in update_tg_cfs_runnable()\n\nA divide-by-zero crash is observed when running hackbench:\n\n [14697.488452] CPU: 112 UID: 0 PID: 124791 Comm: hackbench Not tainted 7.1.0-rc2+\n [14697.492627] RIP: 0010:propagate_entity_load_avg+0x35f/0x3e0\n [14697.506799] <TASK>\n [14697.507411] __dequeue_task+0x2b4/0xc70\n [14697.508677] dequeue_task_fair+0x36/0x370\n [14697.509047] dequeue_task+0x101/0x2f0\n [14697.509426] __schedule+0x1b1/0x1a00\n [14697.510868] anon_pipe_read+0x3da/0x450\n [14697.511400] vfs_read+0x361/0x390\n [14697.512053] __x64_sys_read+0x19/0x30\n\nThe divide-by-zero happens here:\n\n if (scale_load_down(gcfs_rq->load.weight)) {\n load_sum = div_u64(gcfs_rq->avg.load_sum,\n scale_load_down(gcfs_rq->load.weight));\n }\n\ngcfs_rq->load.weight is an insane large value and is truncated\nto the lower 32 bits by div_u64, which happen to be 0.\n\nUsing AI for investigation, the cause is a u32 overflow in\nupdate_tg_cfs_runnable(), and flat pickup became a victim when using\ntg_tasks():\n\n u32 new_sum, divider;\n ...\n new_sum = se->avg.runnable_avg * divider; <-- boom\n\nThe following sequence shows how this triggers the crash:\n\n propagate_entity_load_avg()\n update_tg_cfs_runnable() # u32 overflow corrupts runnable_sum\n\n __update_load_avg_cfs_rq()\n ___update_load_avg() # computes insane runnable_avg\n update_tg_load_avg() # propagates to tg->runnable_avg\n\n update_cfs_group()\n calc_concur_shares()\n tg_tasks() # long-to-int truncation, negative nr\n reweight_entity() # corrupted se->load.weight\n update_load_add() # corrupted cfs_rq->load.weight\n\n propagate_entity_load_avg()\n update_tg_cfs_load()\n div_u64() # divide-by-zero\n\nFix by widening new_sum from u32 to u64 (no need to force tg_tasks()\nto return unsigned long after this fix)"
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"kernel/sched/fair.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "95246d1ec80b8d19d882cd8eb7ad094e63b41bb8",
"lessThan": "39d707097a0820c6e87eff4195f0940e8ff1147e",
"versionType": "git",
"status": "affected"
},
{
"version": "95246d1ec80b8d19d882cd8eb7ad094e63b41bb8",
"lessThan": "69fafae4eb2c9fc9bcff1bcbfcccf5d197434d75",
"versionType": "git",
"status": "affected"
},
{
"version": "95246d1ec80b8d19d882cd8eb7ad094e63b41bb8",
"lessThan": "7cc237e3bc1733928313d2462b413ae441b0eef3",
"versionType": "git",
"status": "affected"
},
{
"version": "95246d1ec80b8d19d882cd8eb7ad094e63b41bb8",
"lessThan": "18fdd0978ec3dda0ff6865cd273e47e022180710",
"versionType": "git",
"status": "affected"
},
{
"version": "95246d1ec80b8d19d882cd8eb7ad094e63b41bb8",
"lessThan": "f94e62d21faad5e244d0874598a4d0ebbc0ea405",
"versionType": "git",
"status": "affected"
},
{
"version": "95246d1ec80b8d19d882cd8eb7ad094e63b41bb8",
"lessThan": "4f166adb5cb0525d9e32d45729fd8f28c80acbee",
"versionType": "git",
"status": "affected"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"kernel/sched/fair.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "5.17",
"status": "affected"
},
{
"version": "0",
"lessThan": "5.17",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.1.188",
"lessThanOrEqual": "6.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.6.157",
"lessThanOrEqual": "6.6.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.110",
"lessThanOrEqual": "6.12.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18.52",
"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.2.6",
"lessThanOrEqual": "7.2.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.3",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {},
"references": [
{
"url": "https://git.kernel.org/stable/c/18fdd0978ec3dda0ff6865cd273e47e022180710",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/39d707097a0820c6e87eff4195f0940e8ff1147e",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/4f166adb5cb0525d9e32d45729fd8f28c80acbee",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/69fafae4eb2c9fc9bcff1bcbfcccf5d197434d75",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/7cc237e3bc1733928313d2462b413ae441b0eef3",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/f94e62d21faad5e244d0874598a4d0ebbc0ea405",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
]
}