CVE-2026-89965
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: nvdimm/btt: reject an arena whose nfree is below the lane count The BTT info block's nfree field, the number of reserve free blocks, is read from the medium without validation. btt_freelist_init() and btt_rtt_init() size the per-lane freelist[] and rtt[] arrays by nfree, but the I/O path indexes them by the lane from nd_region_acquire_lane(), which is bounded by nd_region->num_lanes (ND_MAX_LANES), not by nfree. A crafted or foreign arena whose nfree is below the lane count makes freelist[lane]/rtt[lane] run past the allocation: an out-of-bounds write. btt.rst documents the nlanes = min(nfree, num_cpus) invariant, which the code does not currently honor: num_lanes is ND_MAX_LANES regardless of nfree. Reject an arena whose nfree is below num_lanes at discovery, before the per-lane arrays are allocated, enforcing that invariant.
Severity
HIGH
CVSS score
7.8
(v3.1)
Vulnerability status
Received
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-09-16 11:17:07.033000
Last modified
2026-10-19 09:18:42.880000
View original CVE JSON
{
"id": "CVE-2026-89965",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2026-09-16T11:17:07.033",
"lastModified": "2026-10-19T09:18:42.880",
"vulnStatus": "Received",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "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 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."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"drivers/nvdimm/btt.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "5212e11fde4d40fa627668b4f2222d20db488f71",
"lessThan": "eb491343d2d1784121ad9af91c25b338c28913c3",
"versionType": "git",
"status": "affected"
},
{
"version": "5212e11fde4d40fa627668b4f2222d20db488f71",
"lessThan": "59d5cd1f42b4bab3609512c3cb3d3540d3d21da7",
"versionType": "git",
"status": "affected"
},
{
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"versionType": "git",
"status": "affected"
},
{
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"status": "affected"
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"versionType": "git",
"status": "affected"
},
{
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"versionType": "git",
"status": "affected"
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{
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"versionType": "git",
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{
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}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"drivers/nvdimm/btt.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "4.2",
"status": "affected"
},
{
"version": "0",
"lessThan": "4.2",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "5.10.270",
"lessThanOrEqual": "5.10.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "5.15.221",
"lessThanOrEqual": "5.15.*",
"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": "6.18.51",
"lessThanOrEqual": "6.18.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.2.5",
"lessThanOrEqual": "7.2.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "7.3",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"attackVector": "LOCAL",
"attackComplexity": "LOW",
"privilegesRequired": "LOW",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9
}
]
},
"references": [
{
"url": "https://git.kernel.org/stable/c/59d5cd1f42b4bab3609512c3cb3d3540d3d21da7",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
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{
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}