CVE-2026-89644 (GCVE-0-2026-89644)
Vulnerability from cvelistv5 – Published: 2026-09-11 19:45 – Updated: 2026-10-30 12:32
VLAI
EPSS
VEX
Title
btrfs: fix extent map leak in NOCOW direct I/O write
Summary
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix extent map leak in NOCOW direct I/O write
btrfs_dio_iomap_begin() calls btrfs_get_extent(), which returns an
extent map reference that must be dropped on all exit paths.
For direct writes into a NOCOW range, btrfs_get_blocks_direct_write()
keeps using that extent map and asks btrfs_create_dio_extent() to
allocate the ordered extent. If that fails, for example because
btrfs_alloc_ordered_extent() fails, the function returns the error
without dropping the input extent map. The PREALLOC path avoided this by
dropping the input extent map before replacing it with the newly created
one.
Check the error from btrfs_create_dio_extent() before replacing the
map and drop the input extent map on failure.
Severity
No CVSS data available.
Assigner
References
6 references
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af , < 8d264d35df981e943171ddc09cd6cc1d38c65e17
(git)
Affected: 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af , < cb732d302245b14943a5017015fffa8e6db7a6c0 (git) Affected: 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af , < b7c873765875645b11503f94c9bae2ca80127375 (git) Affected: 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af , < f42efd634c0ae7ba0ce2fc5e30e291b0803b0ae2 (git) Affected: 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af , < 05a1a816eef8b3e4332620a64fc8cf45c4eb5c0d (git) Affected: 5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af , < 3f950867c307c5413d628a153ac44915bd117ffd (git) |
guessed | |
| Linux | Linux |
Affected:
4.7
Unaffected: 0 , < 4.7 (semver) Unaffected: 6.1.191 , ≤ 6.1.* (semver) Unaffected: 6.6.160 , ≤ 6.6.* (semver) Unaffected: 6.12.111 , ≤ 6.12.* (semver) Unaffected: 6.18.50 , ≤ 6.18.* (semver) Unaffected: 7.2.4 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix) |
guessed |
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/btrfs/direct-io.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "8d264d35df981e943171ddc09cd6cc1d38c65e17",
"status": "affected",
"version": "5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af",
"versionType": "git"
},
{
"lessThan": "cb732d302245b14943a5017015fffa8e6db7a6c0",
"status": "affected",
"version": "5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af",
"versionType": "git"
},
{
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"status": "affected",
"version": "5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af",
"versionType": "git"
},
{
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"status": "affected",
"version": "5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af",
"versionType": "git"
},
{
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"status": "affected",
"version": "5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af",
"versionType": "git"
},
{
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"version": "5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"fs/btrfs/direct-io.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.7"
},
{
"lessThan": "4.7",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.191",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.111",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.50",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.4",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.191",
"versionStartIncluding": "4.7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.160",
"versionStartIncluding": "4.7",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.111",
"versionStartIncluding": "4.7",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.50",
"versionStartIncluding": "4.7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2.4",
"versionStartIncluding": "4.7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.3",
"versionStartIncluding": "4.7",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix extent map leak in NOCOW direct I/O write\n\nbtrfs_dio_iomap_begin() calls btrfs_get_extent(), which returns an\nextent map reference that must be dropped on all exit paths.\n\nFor direct writes into a NOCOW range, btrfs_get_blocks_direct_write()\nkeeps using that extent map and asks btrfs_create_dio_extent() to\nallocate the ordered extent. If that fails, for example because\nbtrfs_alloc_ordered_extent() fails, the function returns the error\nwithout dropping the input extent map. The PREALLOC path avoided this by\ndropping the input extent map before replacing it with the newly created\none.\n\nCheck the error from btrfs_create_dio_extent() before replacing the\nmap and drop the input extent map on failure."
}
],
"providerMetadata": {
"dateUpdated": "2026-10-30T12:32:27.002Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/8d264d35df981e943171ddc09cd6cc1d38c65e17"
},
{
"url": "https://git.kernel.org/stable/c/cb732d302245b14943a5017015fffa8e6db7a6c0"
},
{
"url": "https://git.kernel.org/stable/c/b7c873765875645b11503f94c9bae2ca80127375"
},
{
"url": "https://git.kernel.org/stable/c/f42efd634c0ae7ba0ce2fc5e30e291b0803b0ae2"
},
{
"url": "https://git.kernel.org/stable/c/05a1a816eef8b3e4332620a64fc8cf45c4eb5c0d"
},
{
"url": "https://git.kernel.org/stable/c/3f950867c307c5413d628a153ac44915bd117ffd"
}
],
"title": "btrfs: fix extent map leak in NOCOW direct I/O write",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-89644",
"datePublished": "2026-09-11T19:45:36.268Z",
"dateReserved": "2026-09-11T19:38:34.741Z",
"dateUpdated": "2026-10-30T12:32:27.002Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-89644",
"date": "2026-11-11",
"epss": "0.00173",
"percentile": "0.06843"
},
"nvd": {
"cve": {
"affected": [
{
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"product": "Linux",
"programFiles": [
"fs/btrfs/direct-io.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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"versionType": "git"
},
{
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"version": "5f9a8a51d8b95505d8de8b7191ae2ed8c504d4af",
"versionType": "git"
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{
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.7"
},
{
"lessThan": "4.7",
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"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
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},
{
"lessThanOrEqual": "6.6.*",
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"version": "6.6.160",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.111",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.50",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.4",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix extent map leak in NOCOW direct I/O write\n\nbtrfs_dio_iomap_begin() calls btrfs_get_extent(), which returns an\nextent map reference that must be dropped on all exit paths.\n\nFor direct writes into a NOCOW range, btrfs_get_blocks_direct_write()\nkeeps using that extent map and asks btrfs_create_dio_extent() to\nallocate the ordered extent. If that fails, for example because\nbtrfs_alloc_ordered_extent() fails, the function returns the error\nwithout dropping the input extent map. The PREALLOC path avoided this by\ndropping the input extent map before replacing it with the newly created\none.\n\nCheck the error from btrfs_create_dio_extent() before replacing the\nmap and drop the input extent map on failure."
}
],
"id": "CVE-2026-89644",
"lastModified": "2026-10-30T13:20:23.873",
"metrics": {},
"published": "2026-09-11T20:19:50.223",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/05a1a816eef8b3e4332620a64fc8cf45c4eb5c0d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/3f950867c307c5413d628a153ac44915bd117ffd"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/8d264d35df981e943171ddc09cd6cc1d38c65e17"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/b7c873765875645b11503f94c9bae2ca80127375"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/cb732d302245b14943a5017015fffa8e6db7a6c0"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/f42efd634c0ae7ba0ce2fc5e30e291b0803b0ae2"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
},
"redhat_vex": {
"aggregate_severity": "Low",
"current_release_date": "2026-11-06T19:49:20+00:00",
"cve": "CVE-2026-89644",
"id": "CVE-2026-89644",
"initial_release_date": "2026-09-11T00:00:00+00:00",
"product_status:known_affected": "1",
"product_status:known_not_affected": "202",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: btrfs: fix extent map leak in NOCOW direct I/O write",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89644.json",
"version": "3"
}
}
}
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Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
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Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.