{"id":"CVE-2026-93182","title":"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: ha…","summary":"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: ha…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 95246d1ec80b8d19d882cd8eb7ad094e63b41bb8 < 39d707097a0820c6e87eff4195f0940e8ff1147e","Linux >= 95246d1ec80b8d19d882cd8eb7ad094e63b41bb8 < 69fafae4eb2c9fc9bcff1bcbfcccf5d197434d75","Linux >= 95246d1ec80b8d19d882cd8eb7ad094e63b41bb8 < 7cc237e3bc1733928313d2462b413ae441b0eef3","Linux >= 95246d1ec80b8d19d882cd8eb7ad094e63b41bb8 < 18fdd0978ec3dda0ff6865cd273e47e022180710","Linux >= 95246d1ec80b8d19d882cd8eb7ad094e63b41bb8 < f94e62d21faad5e244d0874598a4d0ebbc0ea405","Linux >= 95246d1ec80b8d19d882cd8eb7ad094e63b41bb8 < 4f166adb5cb0525d9e32d45729fd8f28c80acbee","Linux 5.17"],"published":"2026-09-17","updated":"2026-09-17","sourceUpdated":"2026-09-17T17:18:14.153","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-93182","references":[{"url":"https://git.kernel.org/stable/c/18fdd0978ec3dda0ff6865cd273e47e022180710","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/39d707097a0820c6e87eff4195f0940e8ff1147e","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4f166adb5cb0525d9e32d45729fd8f28c80acbee","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/69fafae4eb2c9fc9bcff1bcbfcccf5d197434d75","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7cc237e3bc1733928313d2462b413ae441b0eef3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f94e62d21faad5e244d0874598a4d0ebbc0ea405","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-17T16:21:47.728Z","epss":0.00205,"epssPercentile":0.10892,"slug":"CVE-2026-93182","body":"## Overview\n\nIn 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)\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":[]}