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CVE-2025-68209 (GCVE-0-2025-68209)

Vulnerability from cvelistv5 – Published: 2025-12-16 13:48 – Updated: 2026-05-11 21:48
VLAI
Title
mlx5: Fix default values in create CQ
Summary
In the Linux kernel, the following vulnerability has been resolved: mlx5: Fix default values in create CQ Currently, CQs without a completion function are assigned the mlx5_add_cq_to_tasklet function by default. This is problematic since only user CQs created through the mlx5_ib driver are intended to use this function. Additionally, all CQs that will use doorbells instead of polling for completions must call mlx5_cq_arm. However, the default CQ creation flow leaves a valid value in the CQ's arm_db field, allowing FW to send interrupts to polling-only CQs in certain corner cases. These two factors would allow a polling-only kernel CQ to be triggered by an EQ interrupt and call a completion function intended only for user CQs, causing a null pointer exception. Some areas in the driver have prevented this issue with one-off fixes but did not address the root cause. This patch fixes the described issue by adding defaults to the create CQ flow. It adds a default dummy completion function to protect against null pointer exceptions, and it sets an invalid command sequence number by default in kernel CQs to prevent the FW from sending an interrupt to the CQ until it is armed. User CQs are responsible for their own initialization values. Callers of mlx5_core_create_cq are responsible for changing the completion function and arming the CQ per their needs.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: cdd04f4d4d71cbf93d0d9abe63bc838f47c467fa , < 08469f5393a1a39f26a6e2eb2e8c33187665c1f4 (git)
Affected: cdd04f4d4d71cbf93d0d9abe63bc838f47c467fa , < e5eba42f01340f73888dfe560be2806057c25913 (git)
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Linux Linux Affected: 6.0
Unaffected: 0 , < 6.0 (semver)
Unaffected: 6.17.9 , ≤ 6.17.* (semver)
Unaffected: 6.18 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/infiniband/hw/mlx5/cq.c",
            "drivers/net/ethernet/mellanox/mlx5/core/cq.c",
            "drivers/net/ethernet/mellanox/mlx5/core/en_main.c",
            "drivers/net/ethernet/mellanox/mlx5/core/fpga/conn.c",
            "drivers/net/ethernet/mellanox/mlx5/core/steering/hws/send.c",
            "drivers/net/ethernet/mellanox/mlx5/core/steering/sws/dr_send.c",
            "drivers/vdpa/mlx5/net/mlx5_vnet.c",
            "include/linux/mlx5/cq.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "lessThan": "08469f5393a1a39f26a6e2eb2e8c33187665c1f4",
              "status": "affected",
              "version": "cdd04f4d4d71cbf93d0d9abe63bc838f47c467fa",
              "versionType": "git"
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              "status": "affected",
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/infiniband/hw/mlx5/cq.c",
            "drivers/net/ethernet/mellanox/mlx5/core/cq.c",
            "drivers/net/ethernet/mellanox/mlx5/core/en_main.c",
            "drivers/net/ethernet/mellanox/mlx5/core/fpga/conn.c",
            "drivers/net/ethernet/mellanox/mlx5/core/steering/hws/send.c",
            "drivers/net/ethernet/mellanox/mlx5/core/steering/sws/dr_send.c",
            "drivers/vdpa/mlx5/net/mlx5_vnet.c",
            "include/linux/mlx5/cq.h"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "6.0"
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              "version": "0",
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              "version": "6.17.9",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.18",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.17.9",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18",
                  "versionStartIncluding": "6.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmlx5: Fix default values in create CQ\n\nCurrently, CQs without a completion function are assigned the\nmlx5_add_cq_to_tasklet function by default. This is problematic since\nonly user CQs created through the mlx5_ib driver are intended to use\nthis function.\n\nAdditionally, all CQs that will use doorbells instead of polling for\ncompletions must call mlx5_cq_arm. However, the default CQ creation flow\nleaves a valid value in the CQ\u0027s arm_db field, allowing FW to send\ninterrupts to polling-only CQs in certain corner cases.\n\nThese two factors would allow a polling-only kernel CQ to be triggered\nby an EQ interrupt and call a completion function intended only for user\nCQs, causing a null pointer exception.\n\nSome areas in the driver have prevented this issue with one-off fixes\nbut did not address the root cause.\n\nThis patch fixes the described issue by adding defaults to the create CQ\nflow. It adds a default dummy completion function to protect against\nnull pointer exceptions, and it sets an invalid command sequence number\nby default in kernel CQs to prevent the FW from sending an interrupt to\nthe CQ until it is armed. User CQs are responsible for their own\ninitialization values.\n\nCallers of mlx5_core_create_cq are responsible for changing the\ncompletion function and arming the CQ per their needs."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T21:48:49.590Z",
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        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/08469f5393a1a39f26a6e2eb2e8c33187665c1f4"
        },
        {
          "url": "https://git.kernel.org/stable/c/e5eba42f01340f73888dfe560be2806057c25913"
        }
      ],
      "title": "mlx5: Fix default values in create CQ",
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        "engine": "bippy-1.2.0"
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  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-68209",
    "datePublished": "2025-12-16T13:48:36.098Z",
    "dateReserved": "2025-12-16T13:41:40.255Z",
    "dateUpdated": "2026-05-11T21:48:49.590Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2025-68209",
      "date": "2026-09-14",
      "epss": "0.00185",
      "percentile": "0.08207"
    },
    "microsoft_vex": {
      "current_release_date": "2026-09-12T01:46:09.000Z",
      "cve": "CVE-2025-68209",
      "id": "msrc_CVE-2025-68209",
      "initial_release_date": "2025-12-17T01:04:47.000Z",
      "product_status:known_affected": "15",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "mlx5: Fix default values in create CQ",
      "url": "https://msrc.microsoft.com/csaf/vex/2025/msrc_cve-2025-68209.json",
      "version": "16"
    },
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
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      "cve": "CVE-2025-68209",
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      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2025-68209.json",
      "version": "37"
    }
  }
}



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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.