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GHSA-RC47-M48R-2657

Vulnerability from github – Published: 2026-06-25 09:31 – Updated: 2026-06-28 09:31

Details

In the Linux kernel, the following vulnerability has been resolved:

RDMA/core: Validate cpu_id against nr_cpu_ids in DMAH alloc

The cpu_id attribute supplied by user space through UVERBS_ATTR_ALLOC_DMAH_CPU_ID is passed directly to cpumask_test_cpu() without first verifying that the value is within the valid CPU range.

Passing such untrusted data to cpumask_test_cpu() may lead to an out-of-bounds read of the underlying cpumask bitmap: the helper expands to a test_bit() that indexes the bitmap by cpu_id / BITS_PER_LONG with no bound check.

In addition, on kernels built with CONFIG_DEBUG_PER_CPU_MAPS it trips the WARN_ON_ONCE() in cpumask_check(); combined with panic_on_warn this turns a bad user input into a machine reboot.

Reject any cpu_id that is not smaller than nr_cpu_ids with -EINVAL before it is used.

Reported by Smatch.

Severity

7.1 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-53187"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-787"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-06-25T09:16:36Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/core: Validate cpu_id against nr_cpu_ids in DMAH alloc\n\nThe cpu_id attribute supplied by user space through\nUVERBS_ATTR_ALLOC_DMAH_CPU_ID is passed directly to cpumask_test_cpu()\nwithout first verifying that the value is within the valid CPU range.\n\nPassing such untrusted data to cpumask_test_cpu() may lead to an\nout-of-bounds read of the underlying cpumask bitmap: the helper expands\nto a test_bit() that indexes the bitmap by cpu_id / BITS_PER_LONG with\nno bound check.\n\nIn addition, on kernels built with CONFIG_DEBUG_PER_CPU_MAPS it trips\nthe WARN_ON_ONCE() in cpumask_check(); combined with panic_on_warn this\nturns a bad user input into a machine reboot.\n\nReject any cpu_id that is not smaller than nr_cpu_ids with -EINVAL\nbefore it is used.\n\nReported by Smatch.",
  "id": "GHSA-rc47-m48r-2657",
  "modified": "2026-06-28T09:31:43Z",
  "published": "2026-06-25T09:31:20Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53187"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0efbb6b54ff56300867027d8e0800d0e32226a20"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/323c98a4ff06aa28114f2bf658fb43eb3b536bbc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bd5e818be7964c1689fba2dad9e6bd3a827fee74"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-53187 (GCVE-0-2026-53187)

Vulnerability from cvelistv5 – Published: 2026-06-25 08:39 – Updated: 2026-08-05 12:33

Title

RDMA/core: Validate cpu_id against nr_cpu_ids in DMAH alloc

Summary

In the Linux kernel, the following vulnerability has been resolved: RDMA/core: Validate cpu_id against nr_cpu_ids in DMAH alloc The cpu_id attribute supplied by user space through UVERBS_ATTR_ALLOC_DMAH_CPU_ID is passed directly to cpumask_test_cpu() without first verifying that the value is within the valid CPU range. Passing such untrusted data to cpumask_test_cpu() may lead to an out-of-bounds read of the underlying cpumask bitmap: the helper expands to a test_bit() that indexes the bitmap by cpu_id / BITS_PER_LONG with no bound check. In addition, on kernels built with CONFIG_DEBUG_PER_CPU_MAPS it trips the WARN_ON_ONCE() in cpumask_check(); combined with panic_on_warn this turns a bad user input into a machine reboot. Reject any cpu_id that is not smaller than nr_cpu_ids with -EINVAL before it is used. Reported by Smatch.

Severity

7.1 (High)


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

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/bd5e818be7964c168…
https://git.kernel.org/stable/c/0efbb6b54ff563008…
https://git.kernel.org/stable/c/323c98a4ff06aa281…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: d83edab562a496a42720902a1d2effccd05c37c5 , < bd5e818be7964c1689fba2dad9e6bd3a827fee74 (git) Affected: d83edab562a496a42720902a1d2effccd05c37c5 , < 0efbb6b54ff56300867027d8e0800d0e32226a20 (git) Affected: d83edab562a496a42720902a1d2effccd05c37c5 , < 323c98a4ff06aa28114f2bf658fb43eb3b536bbc (git)
Linux	Linux	Affected: 6.17 Unaffected: 0 , < 6.17 (semver) Unaffected: 6.18.36 , ≤ 6.18.* (semver) Unaffected: 7.0.13 , ≤ 7.0.* (semver) Unaffected: 7.1 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/infiniband/core/uverbs_std_types_dmah.c"
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          "versions": [
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              "versionType": "git"
            },
            {
              "lessThan": "0efbb6b54ff56300867027d8e0800d0e32226a20",
              "status": "affected",
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              "versionType": "git"
            },
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              "lessThan": "323c98a4ff06aa28114f2bf658fb43eb3b536bbc",
              "status": "affected",
              "version": "d83edab562a496a42720902a1d2effccd05c37c5",
              "versionType": "git"
            }
          ]
        },
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            "drivers/infiniband/core/uverbs_std_types_dmah.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.17"
            },
            {
              "lessThan": "6.17",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.36",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "6.17",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/core: Validate cpu_id against nr_cpu_ids in DMAH alloc\n\nThe cpu_id attribute supplied by user space through\nUVERBS_ATTR_ALLOC_DMAH_CPU_ID is passed directly to cpumask_test_cpu()\nwithout first verifying that the value is within the valid CPU range.\n\nPassing such untrusted data to cpumask_test_cpu() may lead to an\nout-of-bounds read of the underlying cpumask bitmap: the helper expands\nto a test_bit() that indexes the bitmap by cpu_id / BITS_PER_LONG with\nno bound check.\n\nIn addition, on kernels built with CONFIG_DEBUG_PER_CPU_MAPS it trips\nthe WARN_ON_ONCE() in cpumask_check(); combined with panic_on_warn this\nturns a bad user input into a machine reboot.\n\nReject any cpu_id that is not smaller than nr_cpu_ids with -EINVAL\nbefore it is used.\n\nReported by Smatch."
        }
      ],
      "metrics": [
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            "baseScore": 7.1,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable path is reached by a local RDMA uverbs ioctl on /dev/infiniband/uverbsN, specifically RDMA_VERBS_IOCTL selecting UVERBS_METHOD_DMAH_ALLOC. It is not exposed by incoming network packets or remote RDMA traffic.\nAC:L - An attacker can supply an out-of-range UVERBS_ATTR_ALLOC_DMAH_CPU_ID directly in one ioctl, with no race or victim-controlled timing requirement. The only deployment prerequisite is an affected RDMA device exposing the DMAH uverbs method.\nPR:L - The uverbs ioctl path has no CAP_* check for DMAH allocation, and RDMA uverbs devices are designed to be usable by non-root users when the device node is accessible. This requires local low-privileged access rather than real administrator privileges.\nUI:N - No victim action is needed after the attacker has local access to the uverbs device. The attacker triggers the bug directly through the ioctl.\nS:U - The bug affects kernel RDMA/core processing within the same host kernel security authority. It does not cross a VM, IOMMU, or separate authorization boundary.\nC:H - The unchecked cpu_id is passed to cpumask_test_cpu(), which expands to test_bit() on current-\u003ecpus_ptr without a bounds check, creating an out-of-bounds kernel memory read. The result influences the returned error/path, making a kernel memory bit oracle defensible.\nI:N - The identified primitive is an out-of-bounds read of a cpumask bitmap and no kernel out-of-bounds write or control-flow corruption was found on the traced path. Passing the value onward only affects TPH steering-tag allocation if the read happens to pass.\nA:H - Large invalid cpu_id values can trigger CONFIG_DEBUG_PER_CPU_MAPS WARN_ON_ONCE(), and with panic_on_warn this reboots the machine. The same unchecked test_bit() can also fault from an out-of-bounds kernel read, making kernel oops/panic availability impact defensible."
            }
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:33:54.299Z",
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        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/bd5e818be7964c1689fba2dad9e6bd3a827fee74"
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        {
          "url": "https://git.kernel.org/stable/c/0efbb6b54ff56300867027d8e0800d0e32226a20"
        },
        {
          "url": "https://git.kernel.org/stable/c/323c98a4ff06aa28114f2bf658fb43eb3b536bbc"
        }
      ],
      "title": "RDMA/core: Validate cpu_id against nr_cpu_ids in DMAH alloc",
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        "engine": "bippy-1.2.0"
      }
    }
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    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-53187",
    "datePublished": "2026-06-25T08:39:00.175Z",
    "dateReserved": "2026-06-09T07:44:35.390Z",
    "dateUpdated": "2026-08-05T12:33:54.299Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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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