{"id":"CVE-2026-89965","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnvdimm/btt: reject an arena whose nfree is below the lane count\n\nThe BTT info block's nfree field, the number of reserve free blocks, is\nread from the medium without va…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnvdimm/btt: reject an arena whose nfree is below the lane count\n\nThe BTT info block's nfree field, the number of reserve free blocks, is\nread from the medium without va…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","vendor":"Linux","product":"Linux","affected":["Linux >= 5212e11fde4d40fa627668b4f2222d20db488f71 < eb491343d2d1784121ad9af91c25b338c28913c3","Linux >= 5212e11fde4d40fa627668b4f2222d20db488f71 < 59d5cd1f42b4bab3609512c3cb3d3540d3d21da7","Linux >= 5212e11fde4d40fa627668b4f2222d20db488f71 < f6c5313aae794ecca8f762c1a3493de5c266f120","Linux >= 5212e11fde4d40fa627668b4f2222d20db488f71 < f9bf05c63b77d000e9c01f3e47af36973887d350","Linux >= 5212e11fde4d40fa627668b4f2222d20db488f71 < 6f79d1a5f2611a3d36e9312be5425cd9cb397c51","Linux >= 5212e11fde4d40fa627668b4f2222d20db488f71 < 6b1faf1f099f7060b5f1f2f0d024132581f1726e","Linux >= 5212e11fde4d40fa627668b4f2222d20db488f71 < 9dfa11cef4750b67591307f2c62e47a23d60e4b7","Linux >= 5212e11fde4d40fa627668b4f2222d20db488f71 < 6a1f2e5ed9267ca19187038ac635393c165213ac","Linux 4.2"],"published":"2026-09-16","updated":"2026-09-16","sourceUpdated":"2026-09-16T15:18:20.830","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-89965","references":[{"url":"https://git.kernel.org/stable/c/59d5cd1f42b4bab3609512c3cb3d3540d3d21da7","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6a1f2e5ed9267ca19187038ac635393c165213ac","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6b1faf1f099f7060b5f1f2f0d024132581f1726e","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6f79d1a5f2611a3d36e9312be5425cd9cb397c51","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/9dfa11cef4750b67591307f2c62e47a23d60e4b7","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/eb491343d2d1784121ad9af91c25b338c28913c3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f6c5313aae794ecca8f762c1a3493de5c266f120","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f9bf05c63b77d000e9c01f3e47af36973887d350","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-16T10:53:53.958Z","epss":0.00164,"epssPercentile":0.06047,"slug":"CVE-2026-89965","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnvdimm/btt: reject an arena whose nfree is below the lane count\n\nThe BTT info block's nfree field, the number of reserve free blocks, is\nread from the medium without validation.  btt_freelist_init() and\nbtt_rtt_init() size the per-lane freelist[] and rtt[] arrays by nfree,\nbut the I/O path indexes them by the lane from nd_region_acquire_lane(),\nwhich is bounded by nd_region->num_lanes (ND_MAX_LANES), not by nfree.\nA crafted or foreign arena whose nfree is below the lane count makes\nfreelist[lane]/rtt[lane] run past the allocation: an out-of-bounds write.\n\nbtt.rst documents the nlanes = min(nfree, num_cpus) invariant, which the\ncode does not currently honor: num_lanes is ND_MAX_LANES regardless of\nnfree.  Reject an arena whose nfree is below num_lanes at discovery,\nbefore the per-lane arrays are allocated, enforcing that invariant.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[{"seq":205083,"id":"CVE-2026-89965","ts":1789570705156,"field":"cvss","old":null,"new":"7.8"},{"seq":205082,"id":"CVE-2026-89965","ts":1789570705156,"field":"severity","old":"none","new":"high"}]}