CVE-2026-68442 (GCVE-0-2026-68442)
Vulnerability from cvelistv5 – Published: 2026-08-12 00:07 – Updated: 2026-08-12 00:07
VLAI
EPSS
VEX
Title
btrfs: don't propagate EXTENT_FLAG_LOGGING to split extent maps
Summary
In the Linux kernel, the following vulnerability has been resolved:
btrfs: don't propagate EXTENT_FLAG_LOGGING to split extent maps
When btrfs_drop_extent_map_range() splits an extent map, the new split
maps inherit the original map's flags through a local 'flags' variable.
Commit f86f7a75e2fb ("btrfs: use the flags of an extent map to identify
the compression type") changed the EXTENT_FLAG_LOGGING clearing to
operate on em->flags instead of that local 'flags' copy, so a split of
an extent map that is currently being logged wrongly inherits
EXTENT_FLAG_LOGGING.
The flag is then never cleared on the split, and when it is freed while
still on the inode's modified_extents list (for example by the extent
map shrinker) it trips the WARN_ON(!list_empty(&em->list)) in
btrfs_free_extent_map() and leads to a use-after-free.
Clear EXTENT_FLAG_LOGGING from the local 'flags' copy used for the
splits and only clear EXTENT_FLAG_PINNED from em->flags, restoring the
behaviour prior to f86f7a75e2fb.
Severity
No CVSS data available.
Assigner
References
Impacted products
2 products
| Vendor | Product | Version | |
|---|---|---|---|
| Linux | Linux |
Affected:
f86f7a75e2fb5fd7d31d00eab8a392f97ba42ce9 , < 2a9246a424f45f33a1b8367052611ebe874868ad
(git)
Affected: f86f7a75e2fb5fd7d31d00eab8a392f97ba42ce9 , < 9304713b70e7e1450e3a76e758836fe5391bfa95 (git) Affected: f86f7a75e2fb5fd7d31d00eab8a392f97ba42ce9 , < 0e465c63f103a5ce6849614d6bda048d70eebec8 (git) Affected: f86f7a75e2fb5fd7d31d00eab8a392f97ba42ce9 , < 5eff4d5b17fa1950e80bfd1ba43dc0699e61a644 (git) |
|
| Linux | Linux |
Affected:
6.8
Unaffected: 0 , < 6.8 (semver) Unaffected: 6.12.101 , ≤ 6.12.* (semver) Unaffected: 6.18.42 , ≤ 6.18.* (semver) Unaffected: 7.1.6 , ≤ 7.1.* (semver) Unaffected: 7.2-rc5 , ≤ * (original_commit_for_fix) |
{
"containers": {
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"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"fs/btrfs/extent_map.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "2a9246a424f45f33a1b8367052611ebe874868ad",
"status": "affected",
"version": "f86f7a75e2fb5fd7d31d00eab8a392f97ba42ce9",
"versionType": "git"
},
{
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"status": "affected",
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"versionType": "git"
},
{
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"status": "affected",
"version": "f86f7a75e2fb5fd7d31d00eab8a392f97ba42ce9",
"versionType": "git"
},
{
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"status": "affected",
"version": "f86f7a75e2fb5fd7d31d00eab8a392f97ba42ce9",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"fs/btrfs/extent_map.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.8"
},
{
"lessThan": "6.8",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.101",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.42",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.6",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2-rc5",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.101",
"versionStartIncluding": "6.8",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.42",
"versionStartIncluding": "6.8",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.6",
"versionStartIncluding": "6.8",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2-rc5",
"versionStartIncluding": "6.8",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: don\u0027t propagate EXTENT_FLAG_LOGGING to split extent maps\n\nWhen btrfs_drop_extent_map_range() splits an extent map, the new split\nmaps inherit the original map\u0027s flags through a local \u0027flags\u0027 variable.\nCommit f86f7a75e2fb (\"btrfs: use the flags of an extent map to identify\nthe compression type\") changed the EXTENT_FLAG_LOGGING clearing to\noperate on em-\u003eflags instead of that local \u0027flags\u0027 copy, so a split of\nan extent map that is currently being logged wrongly inherits\nEXTENT_FLAG_LOGGING.\n\nThe flag is then never cleared on the split, and when it is freed while\nstill on the inode\u0027s modified_extents list (for example by the extent\nmap shrinker) it trips the WARN_ON(!list_empty(\u0026em-\u003elist)) in\nbtrfs_free_extent_map() and leads to a use-after-free.\n\nClear EXTENT_FLAG_LOGGING from the local \u0027flags\u0027 copy used for the\nsplits and only clear EXTENT_FLAG_PINNED from em-\u003eflags, restoring the\nbehaviour prior to f86f7a75e2fb."
}
],
"providerMetadata": {
"dateUpdated": "2026-08-12T00:07:31.981Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/2a9246a424f45f33a1b8367052611ebe874868ad"
},
{
"url": "https://git.kernel.org/stable/c/9304713b70e7e1450e3a76e758836fe5391bfa95"
},
{
"url": "https://git.kernel.org/stable/c/0e465c63f103a5ce6849614d6bda048d70eebec8"
},
{
"url": "https://git.kernel.org/stable/c/5eff4d5b17fa1950e80bfd1ba43dc0699e61a644"
}
],
"title": "btrfs: don\u0027t propagate EXTENT_FLAG_LOGGING to split extent maps",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-68442",
"datePublished": "2026-08-12T00:07:31.981Z",
"dateReserved": "2026-07-30T09:28:09.394Z",
"dateUpdated": "2026-08-12T00:07:31.981Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-68442",
"date": "2026-08-12",
"epss": "0.00157",
"percentile": "0.05311"
},
"nvd": "{\"cve\":{\"id\":\"CVE-2026-68442\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-12T00:17:44.477\",\"lastModified\":\"2026-08-12T00:17:44.477\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nbtrfs: don\u0027t propagate EXTENT_FLAG_LOGGING to split extent maps\\n\\nWhen btrfs_drop_extent_map_range() splits an extent map, the new split\\nmaps inherit the original map\u0027s flags through a local \u0027flags\u0027 variable.\\nCommit f86f7a75e2fb (\\\"btrfs: use the flags of an extent map to identify\\nthe compression type\\\") changed the EXTENT_FLAG_LOGGING clearing to\\noperate on em-\u003eflags instead of that local \u0027flags\u0027 copy, so a split of\\nan extent map that is currently being logged wrongly inherits\\nEXTENT_FLAG_LOGGING.\\n\\nThe flag is then never cleared on the split, and when it is freed while\\nstill on the inode\u0027s modified_extents list (for example by the extent\\nmap shrinker) it trips the WARN_ON(!list_empty(\u0026em-\u003elist)) in\\nbtrfs_free_extent_map() and leads to a use-after-free.\\n\\nClear EXTENT_FLAG_LOGGING from the local \u0027flags\u0027 copy used for the\\nsplits and only clear EXTENT_FLAG_PINNED from em-\u003eflags, restoring the\\nbehaviour prior to f86f7a75e2fb.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"fs/btrfs/extent_map.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"f86f7a75e2fb5fd7d31d00eab8a392f97ba42ce9\",\"lessThan\":\"2a9246a424f45f33a1b8367052611ebe874868ad\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"f86f7a75e2fb5fd7d31d00eab8a392f97ba42ce9\",\"lessThan\":\"9304713b70e7e1450e3a76e758836fe5391bfa95\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"f86f7a75e2fb5fd7d31d00eab8a392f97ba42ce9\",\"lessThan\":\"0e465c63f103a5ce6849614d6bda048d70eebec8\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"f86f7a75e2fb5fd7d31d00eab8a392f97ba42ce9\",\"lessThan\":\"5eff4d5b17fa1950e80bfd1ba43dc0699e61a644\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"fs/btrfs/extent_map.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.8\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.8\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.101\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.42\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.6\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2-rc5\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0e465c63f103a5ce6849614d6bda048d70eebec8\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/2a9246a424f45f33a1b8367052611ebe874868ad\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/5eff4d5b17fa1950e80bfd1ba43dc0699e61a644\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/9304713b70e7e1450e3a76e758836fe5391bfa95\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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