CVE-2026-43271 (GCVE-0-2026-43271)
Vulnerability from cvelistv5 – Published: 2026-05-06 11:28 – Updated: 2026-05-07 17:15
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:
0ba959774e93911caff596de6391f085fb640ac4 , < a61c1bc84c4a0f1e7c2fe55b0f43d7d94af4adf1
(git)
Affected: 0ba959774e93911caff596de6391f085fb640ac4 , < dec123825c1ed74d98fd5fc7571a851dea4f46ff (git) Affected: 0ba959774e93911caff596de6391f085fb640ac4 , < 721599e837d3f4c0e6cc14da059612c017b6d3ec (git) Affected: 0ba959774e93911caff596de6391f085fb640ac4 , < dceb5a843910004cb118148e267036104fc3ee43 (git) Affected: 0ba959774e93911caff596de6391f085fb640ac4 , < f150e753cb8dd756085f46e86f2c35ce472e0a3c (git) |
||
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"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."
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},
{
"url": "https://git.kernel.org/stable/c/f150e753cb8dd756085f46e86f2c35ce472e0a3c"
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],
"title": "md-cluster: fix NULL pointer dereference in process_metadata_update",
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"cveId": "CVE-2026-43271",
"datePublished": "2026-05-06T11:28:55.507Z",
"dateReserved": "2026-05-01T14:12:55.998Z",
"dateUpdated": "2026-05-07T17:15:17.948Z",
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"date": "2026-05-09",
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}
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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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