{"cve":"CVE-2026-64458","nvd":{"published":"2026-07-25T10:17:30.943","modified":"2026-08-17T05:17:50.980","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/damon/ops-common: handle extreme intervals in damon_hot_score()\n\nFix three issues in damon_hot_score() that comes from wrong handling of\nextreme (zero or too high) monitoring intervals user setup.\n\nWhen the user sets sampling interval zero, damon_max_nr_accesses(), which\nis called from damon_hot_score(), causes a divide-by-zero.  Needless to\nsay, it is a problem.\n\nWhen the user sets the aggregation interval zero, the function returns\nzero.  It is wrong, since the real maximum nr_acceses in the setup should\nbe one.  Worse yet, it can cause another divide-by-zero from its caller,\ndamon_hot_score(), since it uses damon_max_nr_accesses() return value as a\ndenominator.\n\nWhen the user sets the aggregation interval very high, damon_hot_score()\ncould return a value out of [0, DAMOS_MAX_SCORE] range.  Since the return\nvalue is used as an index to the regions_score_histogram array, which is\nDAMOS_MAX_SCORE+1 size, it causes out of bounds array access.\n\nThe issues can be relatively easily reproduced like below.  The sysfs\nwrite permission is required, though.\n\n    # ./damo start --damos_action lru_prio --damos_quota_space 100M \\\n            --damos_quota_interval 1s\n    # cd /sys/kernel/mm/damon/admin/kdamonds/0\n    # echo 0 > contexts/0/monitoring_attrs/intervals/sample_us\n    # echo 0 > contexts/0/monitoring_attrs/intervals/aggr_us\n    # echo commit > state\n    # dmesg\n    [...]\n    [  131.329762] Oops: divide error: 0000 [#1] SMP NOPTI\n    [...]\n    [  131.336089] RIP: 0010:damon_hot_score+0x27/0xd0\n    [...]\n\nFix the divide-by-zero intervals problems by explicitly handling the zero\nintervals in damon_max_nr_accesses().  Fix the out-of-bound array access\nby applying [0, DAMOS_MAX_SCORE] bounds before returning from\ndamon_hot_score().\n\nThe issue was discovered [1] by Sashiko.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/35d4a3cf70a855b50e53189ac2f8463e20a02046","https://git.kernel.org/stable/c/58321b4e6e4f0f412069ab27ccdd56292757343a","https://git.kernel.org/stable/c/74fef68d521150281e36cdaa20e9e1ee3e3aa146","https://git.kernel.org/stable/c/76e415ea88d20f022ed5cfcf78c50e156a267e91","https://git.kernel.org/stable/c/9c8f31eaae6140ecadec0c07320498a944556de2"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:46:40.600842820+00:00"},"epss":{"cve":"CVE-2026-64458","score":0.0018,"percentile":0.07605,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}