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CVE-2025-37906 (GCVE-0-2025-37906)

Vulnerability from cvelistv5 – Published: 2025-05-20 15:21 – Updated: 2026-08-05 11:58
VLAI
Title
ublk: fix race between io_uring_cmd_complete_in_task and ublk_cancel_cmd
Summary
In the Linux kernel, the following vulnerability has been resolved: ublk: fix race between io_uring_cmd_complete_in_task and ublk_cancel_cmd ublk_cancel_cmd() calls io_uring_cmd_done() to complete uring_cmd, but we may have scheduled task work via io_uring_cmd_complete_in_task() for dispatching request, then kernel crash can be triggered. Fix it by not trying to canceling the command if ublk block request is started.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 216c8f5ef0f209a3797292c487bdaa6991ab4b92 , < fb2eb9ddf556f93fef45201e1f9d2b8674bcc975 (git)
Affected: 216c8f5ef0f209a3797292c487bdaa6991ab4b92 , < f40139fde5278d81af3227444fd6e76a76b9506d (git)
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Linux Linux Affected: 6.7
Unaffected: 0 , < 6.7 (semver)
Unaffected: 6.14.6 , ≤ 6.14.* (semver)
Unaffected: 6.15 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/block/ublk_drv.c"
          ],
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          "vendor": "Linux",
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              "status": "affected",
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              "versionType": "git"
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              "status": "unaffected",
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nublk: fix race between io_uring_cmd_complete_in_task and ublk_cancel_cmd\n\nublk_cancel_cmd() calls io_uring_cmd_done() to complete uring_cmd, but\nwe may have scheduled task work via io_uring_cmd_complete_in_task() for\ndispatching request, then kernel crash can be triggered.\n\nFix it by not trying to canceling the command if ublk block request is\nstarted."
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              "value": "AV:L - The race is reached only through local interfaces \u2014 `/dev/ublk-control` and `/dev/ublkc*` io_uring passthrough commands plus block I/O to `/dev/ublkb*`. There is no remote or adjacent-network path into ublk_drv.\nAC:L - The attacker owns both sides of the race: one thread submits I/O to the ublk block device (queueing `ublk_cmd_tw_cb` task work) while another tears down the io_uring ring or issues `UBLK_CMD_STOP_DEV`, driving `ublk_cancel_cmd()`. The window can be hit repeatedly in a loop with high queue depth until it lands.\nPR:L - ublk explicitly supports `UBLK_F_UNPRIVILEGED_DEV`, where `ublk_ctrl_add_dev()` accepts non-`CAP_SYS_ADMIN` callers and all later control commands gate only on file permissions of `/dev/ublkc*`, so an ordinary local user (including inside a container) can create and drive the device. Only basic local-user access is needed, not real root.\nUI:N - The attacking process performs every step itself \u2014 creating the ublk device, issuing I/O, and triggering cancellation. No victim action or interaction is required.\nS:U - The corruption is confined to kernel heap objects (`io_kiocb`) within the same security authority; the ublk driver and io_uring both run in the kernel\u0027s own scope. No VM, IOMMU, or sandbox boundary is crossed.\nC:H - The freed io_uring request is dereferenced and re-completed, so an attacker who reclaims the slab object controls its contents and can have kernel data posted back through the CQE and the ublk io path. Per UAF guidance this constitutes a path to arbitrary kernel memory disclosure.\nI:H - The second `io_uring_cmd_done()` writes result fields into and relinks a freed `io_kiocb`, and the request is freed twice \u2014 a write-after-free plus double-free on a well-known io_uring slab that is a standard heap-spray target for control-flow hijack. This is high-integrity memory corruption, not a bounded write.\nA:H - The commit states plainly that \"kernel crash can be triggered,\" and the double completion corrupts io_uring\u0027s completion/task-work lists. Any unprivileged local user with a ublk device can panic the machine on demand."
            }
          ]
        }
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        "dateUpdated": "2026-08-05T11:58:13.306Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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    "assignerShortName": "Linux",
    "cveId": "CVE-2025-37906",
    "datePublished": "2025-05-20T15:21:39.633Z",
    "dateReserved": "2025-04-16T04:51:23.966Z",
    "dateUpdated": "2026-08-05T11:58:13.306Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
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      "cve": "CVE-2025-37906",
      "date": "2026-09-17",
      "epss": "0.00129",
      "percentile": "0.02902"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-37906\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-05-20T16:15:27.070\",\"lastModified\":\"2026-07-30T06:22:31.523\",\"vulnStatus\":\"Modified\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nublk: fix race between io_uring_cmd_complete_in_task and ublk_cancel_cmd\\n\\nublk_cancel_cmd() calls io_uring_cmd_done() to complete uring_cmd, but\\nwe may have scheduled task work via io_uring_cmd_complete_in_task() for\\ndispatching request, then kernel crash can be triggered.\\n\\nFix it by not trying to canceling the command if ublk block request is\\nstarted.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: ublk: se corrige la ejecuci\u00f3n entre io_uring_cmd_complete_in_task y ublk_cancel_cmd. ublk_cancel_cmd() llama a io_uring_cmd_done() para completar uring_cmd, pero es posible que hayamos programado el trabajo de la tarea mediante io_uring_cmd_complete_in_task() para el env\u00edo de la solicitud, lo que puede provocar un fallo del kernel. Para solucionarlo, no intente cancelar el comando si se inicia la solicitud de bloqueo de ublk.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/block/ublk_drv.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"216c8f5ef0f209a3797292c487bdaa6991ab4b92\",\"lessThan\":\"fb2eb9ddf556f93fef45201e1f9d2b8674bcc975\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"216c8f5ef0f209a3797292c487bdaa6991ab4b92\",\"lessThan\":\"f40139fde5278d81af3227444fd6e76a76b9506d\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/block/ublk_drv.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.7\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.7\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.14.6\",\"lessThanOrEqual\":\"6.14.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.15\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9},{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":4.7,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.0,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-362\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"6.7\",\"versionEndExcluding\":\"6.14.6\",\"matchCriteriaId\":\"7C6CDFC7-5547-4D8F-8407-031E5A221969\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.15:rc1:*:*:*:*:*:*\",\"matchCriteriaId\":\"8D465631-2980-487A-8E65-40AE2B9F8ED1\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.15:rc2:*:*:*:*:*:*\",\"matchCriteriaId\":\"4C9D071F-B28E-46EC-AC61-22B913390211\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:6.15:rc3:*:*:*:*:*:*\",\"matchCriteriaId\":\"13FC0DDE-E513-465E-9E81-515702D49B74\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/f40139fde5278d81af3227444fd6e76a76b9506d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/fb2eb9ddf556f93fef45201e1f9d2b8674bcc975\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-07-30T09:29:18+00:00",
      "cve": "CVE-2025-37906",
      "id": "CVE-2025-37906",
      "initial_release_date": "2025-05-20T00:00:00+00:00",
      "product_status:known_affected": "76",
      "product_status:known_not_affected": "198",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: Linux kernel: ublk race condition causes kernel crash",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-37906.json",
      "version": "3"
    }
  }
}



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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

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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.


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.