Vulnerability-Lookup

CVE-2025-38621 (GCVE-0-2025-38621)

Vulnerability from cvelistv5 – Published: 2025-08-22 16:00 – Updated: 2026-09-07 15:44

Title

md: make rdev_addable usable for rcu mode

Summary

In the Linux kernel, the following vulnerability has been resolved: md: make rdev_addable usable for rcu mode Our testcase trigger panic: BUG: kernel NULL pointer dereference, address: 00000000000000e0 ... Oops: Oops: 0000 [#1] SMP NOPTI CPU: 2 UID: 0 PID: 85 Comm: kworker/2:1 Not tainted 6.16.0+ #94 PREEMPT(none) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 Workqueue: md_misc md_start_sync RIP: 0010:rdev_addable+0x4d/0xf0 ... Call Trace: <TASK> md_start_sync+0x329/0x480 process_one_work+0x226/0x6d0 worker_thread+0x19e/0x340 kthread+0x10f/0x250 ret_from_fork+0x14d/0x180 ret_from_fork_asm+0x1a/0x30 </TASK> Modules linked in: raid10 CR2: 00000000000000e0 ---[ end trace 0000000000000000 ]--- RIP: 0010:rdev_addable+0x4d/0xf0 md_spares_need_change in md_start_sync will call rdev_addable which protected by rcu_read_lock/rcu_read_unlock. This rcu context will help protect rdev won't be released, but rdev->mddev will be set to NULL before we call synchronize_rcu in md_kick_rdev_from_array. Fix this by using READ_ONCE and check does rdev->mddev still alive.

Severity

5.5 (Medium)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/d713e105a6137d3f5…
https://git.kernel.org/stable/c/b5fbe940862339cdc…
https://git.kernel.org/stable/c/13017b427118f4311…

Impacted products

2 products

Vendor	Product	Version	CPE status
Linux	Linux	Affected: bc08041b32abe6c9824f78735bac22018eabfc06 , < d713e105a6137d3f54f09d4d9e2273482057ca17 (git) Affected: bc08041b32abe6c9824f78735bac22018eabfc06 , < b5fbe940862339cdcc34dea7a057ad18d18fa137 (git) Affected: bc08041b32abe6c9824f78735bac22018eabfc06 , < 13017b427118f4311471ee47df74872372ca8482 (git)	guessed
Linux	Linux	Affected: 6.7 Unaffected: 0 , < 6.7 (semver) Unaffected: 6.12.109 , ≤ 6.12.* (semver) Unaffected: 6.16.1 , ≤ 6.16.* (semver) Unaffected: 6.17 , ≤ * (original_commit_for_fix)	guessed

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{
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        {
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          "product": "Linux",
          "programFiles": [
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          "vendor": "Linux",
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              "status": "affected",
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              "version": "6.7"
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              "status": "unaffected",
              "version": "0",
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              "versionType": "semver"
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmd: make rdev_addable usable for rcu mode\n\nOur testcase trigger panic:\n\nBUG: kernel NULL pointer dereference, address: 00000000000000e0\n...\nOops: Oops: 0000 [#1] SMP NOPTI\nCPU: 2 UID: 0 PID: 85 Comm: kworker/2:1 Not tainted 6.16.0+ #94\nPREEMPT(none)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS\n1.16.1-2.fc37 04/01/2014\nWorkqueue: md_misc md_start_sync\nRIP: 0010:rdev_addable+0x4d/0xf0\n...\nCall Trace:\n \u003cTASK\u003e\n md_start_sync+0x329/0x480\n process_one_work+0x226/0x6d0\n worker_thread+0x19e/0x340\n kthread+0x10f/0x250\n ret_from_fork+0x14d/0x180\n ret_from_fork_asm+0x1a/0x30\n \u003c/TASK\u003e\nModules linked in: raid10\nCR2: 00000000000000e0\n---[ end trace 0000000000000000 ]---\nRIP: 0010:rdev_addable+0x4d/0xf0\n\nmd_spares_need_change in md_start_sync will call rdev_addable which\nprotected by rcu_read_lock/rcu_read_unlock. This rcu context will help\nprotect rdev won\u0027t be released, but rdev-\u003emddev will be set to NULL\nbefore we call synchronize_rcu in md_kick_rdev_from_array. Fix this by\nusing READ_ONCE and check does rdev-\u003emddev still alive."
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        },
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          "url": "https://git.kernel.org/stable/c/13017b427118f4311471ee47df74872372ca8482"
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      "title": "md: make rdev_addable usable for rcu mode",
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    "cveId": "CVE-2025-38621",
    "datePublished": "2025-08-22T16:00:30.308Z",
    "dateReserved": "2025-04-16T04:51:24.029Z",
    "dateUpdated": "2026-09-07T15:44:48.481Z",
    "state": "PUBLISHED"
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      "date": "2026-09-16",
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      "percentile": "0.05414"
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This rcu context will help\\nprotect rdev won\u0027t be released, but rdev-\u003emddev will be set to NULL\\nbefore we call synchronize_rcu in md_kick_rdev_from_array. Fix this by\\nusing READ_ONCE and check does rdev-\u003emddev still alive.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: md: hacer que rdev_addable sea utilizable para el modo rcu Nuestro caso de prueba activa el p\u00e1nico: ERROR: desreferencia de puntero NULL del kernel, direcci\u00f3n: 00000000000000e0 ... Oops: Oops: 0000 [#1] SMP NOPTI CPU: 2 UID: 0 PID: 85 Comm: kworker/2:1 No contaminado 6.16.0+ #94 PREEMPT(none) Nombre del hardware: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 01/04/2014 Cola de trabajo: md_misc md_start_sync RIP: 0010:rdev_addable+0x4d/0xf0 ... Rastreo de llamadas:  M\u00f3dulos vinculados en: raid10 CR2: 00000000000000e0 ---[ fin de seguimiento 000000000000000 ]--- RIP: 0010:rdev_addable+0x4d/0xf0 md_spares_need_change en md_start_sync llamar\u00e1 a rdev_addable que est\u00e1 protegido por rcu_read_lock/rcu_read_unlock. Este contexto rcu ayudar\u00e1 a proteger rdev, ya que no se liberar\u00e1, pero rdev-\u0026gt;mddev se establecer\u00e1 en NULL antes de llamar a synchronize_rcu en md_kick_rdev_from_array. 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    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-06-30T10:21:51+00:00",
      "cve": "CVE-2025-38621",
      "id": "CVE-2025-38621",
      "initial_release_date": "2025-08-22T00:00:00+00:00",
      "product_status:known_affected": "198",
      "product_status:known_not_affected": "76",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: md: make rdev_addable usable for rcu mode",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-38621.json",
      "version": "3"
    }
  }
}

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.

Detection rules are retrieved from Rulezet.

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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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CVE-2025-38621 (GCVE-0-2025-38621)

Tags

Sightings

Nomenclature

Related by attack behaviour