CVE-2026-43271 (GCVE-0-2026-43271)
Vulnerability from cvelistv5 – Published: 2026-05-06 11:28 – Updated: 2026-05-06 11:28
VLAI?
Title
md-cluster: fix NULL pointer dereference in process_metadata_update
Summary
In the Linux kernel, the following vulnerability has been resolved:
md-cluster: fix NULL pointer dereference in process_metadata_update
The function process_metadata_update() blindly dereferences the 'thread'
pointer (acquired via rcu_dereference_protected) within the wait_event()
macro.
While the code comment states "daemon thread must exist", there is a valid
race condition window during the MD array startup sequence (md_run):
1. bitmap_load() is called, which invokes md_cluster_ops->join().
2. join() starts the "cluster_recv" thread (recv_daemon).
3. At this point, recv_daemon is active and processing messages.
4. However, mddev->thread (the main MD thread) is not initialized until
later in md_run().
If a METADATA_UPDATED message is received from a remote node during this
specific window, process_metadata_update() will be called while
mddev->thread is still NULL, leading to a kernel panic.
To fix this, we must validate the 'thread' pointer. If it is NULL, we
release the held lock (no_new_dev_lockres) and return early, safely
ignoring the update request as the array is not yet fully ready to
process it.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Affected:
1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < a61c1bc84c4a0f1e7c2fe55b0f43d7d94af4adf1
(git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < dec123825c1ed74d98fd5fc7571a851dea4f46ff (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 721599e837d3f4c0e6cc14da059612c017b6d3ec (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < dceb5a843910004cb118148e267036104fc3ee43 (git) Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < f150e753cb8dd756085f46e86f2c35ce472e0a3c (git) |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/md/md-cluster.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "a61c1bc84c4a0f1e7c2fe55b0f43d7d94af4adf1",
"status": "affected",
"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
"versionType": "git"
},
{
"lessThan": "dec123825c1ed74d98fd5fc7571a851dea4f46ff",
"status": "affected",
"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
"versionType": "git"
},
{
"lessThan": "721599e837d3f4c0e6cc14da059612c017b6d3ec",
"status": "affected",
"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
"versionType": "git"
},
{
"lessThan": "dceb5a843910004cb118148e267036104fc3ee43",
"status": "affected",
"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
"versionType": "git"
},
{
"lessThan": "f150e753cb8dd756085f46e86f2c35ce472e0a3c",
"status": "affected",
"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/md/md-cluster.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.128",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.75",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.16",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.19.*",
"status": "unaffected",
"version": "6.19.6",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.128",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.75",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.16",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.19.6",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmd-cluster: fix NULL pointer dereference in process_metadata_update\n\nThe function process_metadata_update() blindly dereferences the \u0027thread\u0027\npointer (acquired via rcu_dereference_protected) within the wait_event()\nmacro.\n\nWhile the code comment states \"daemon thread must exist\", there is a valid\nrace condition window during the MD array startup sequence (md_run):\n\n1. bitmap_load() is called, which invokes md_cluster_ops-\u003ejoin().\n2. join() starts the \"cluster_recv\" thread (recv_daemon).\n3. At this point, recv_daemon is active and processing messages.\n4. However, mddev-\u003ethread (the main MD thread) is not initialized until\n later in md_run().\n\nIf a METADATA_UPDATED message is received from a remote node during this\nspecific window, process_metadata_update() will be called while\nmddev-\u003ethread is still NULL, leading to a kernel panic.\n\nTo fix this, we must validate the \u0027thread\u0027 pointer. If it is NULL, we\nrelease the held lock (no_new_dev_lockres) and return early, safely\nignoring the update request as the array is not yet fully ready to\nprocess it."
}
],
"providerMetadata": {
"dateUpdated": "2026-05-06T11:28:55.507Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/a61c1bc84c4a0f1e7c2fe55b0f43d7d94af4adf1"
},
{
"url": "https://git.kernel.org/stable/c/dec123825c1ed74d98fd5fc7571a851dea4f46ff"
},
{
"url": "https://git.kernel.org/stable/c/721599e837d3f4c0e6cc14da059612c017b6d3ec"
},
{
"url": "https://git.kernel.org/stable/c/dceb5a843910004cb118148e267036104fc3ee43"
},
{
"url": "https://git.kernel.org/stable/c/f150e753cb8dd756085f46e86f2c35ce472e0a3c"
}
],
"title": "md-cluster: fix NULL pointer dereference in process_metadata_update",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-43271",
"datePublished": "2026-05-06T11:28:55.507Z",
"dateReserved": "2026-05-01T14:12:55.998Z",
"dateUpdated": "2026-05-06T11:28:55.507Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"nvd": "{\"cve\":{\"id\":\"CVE-2026-43271\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-05-06T12:16:48.313\",\"lastModified\":\"2026-05-06T13:07:51.607\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nmd-cluster: fix NULL pointer dereference in process_metadata_update\\n\\nThe function process_metadata_update() blindly dereferences the \u0027thread\u0027\\npointer (acquired via rcu_dereference_protected) within the wait_event()\\nmacro.\\n\\nWhile the code comment states \\\"daemon thread must exist\\\", there is a valid\\nrace condition window during the MD array startup sequence (md_run):\\n\\n1. bitmap_load() is called, which invokes md_cluster_ops-\u003ejoin().\\n2. join() starts the \\\"cluster_recv\\\" thread (recv_daemon).\\n3. At this point, recv_daemon is active and processing messages.\\n4. However, mddev-\u003ethread (the main MD thread) is not initialized until\\n later in md_run().\\n\\nIf a METADATA_UPDATED message is received from a remote node during this\\nspecific window, process_metadata_update() will be called while\\nmddev-\u003ethread is still NULL, leading to a kernel panic.\\n\\nTo fix this, we must validate the \u0027thread\u0027 pointer. If it is NULL, we\\nrelease the held lock (no_new_dev_lockres) and return early, safely\\nignoring the update request as the array is not yet fully ready to\\nprocess it.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/721599e837d3f4c0e6cc14da059612c017b6d3ec\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/a61c1bc84c4a0f1e7c2fe55b0f43d7d94af4adf1\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/dceb5a843910004cb118148e267036104fc3ee43\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/dec123825c1ed74d98fd5fc7571a851dea4f46ff\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f150e753cb8dd756085f46e86f2c35ce472e0a3c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}
Loading…
Loading…
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.
Loading…
Loading…