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CVE-2026-74296 (GCVE-0-2026-74296)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:58 – Updated: 2026-08-17 05:45
VLAI
Title
RDMA/mlx5: Release the HW‑provided UAR index rather than the SW one
Summary
In the Linux kernel, the following vulnerability has been resolved: RDMA/mlx5: Release the HW‑provided UAR index rather than the SW one Free the UAR index returned by the hardware.
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: 4ed131d0bb1597ce12fff22d9d7fc9720a6e8cf0 , < 80f1f49f53a42733e60c90e0ec545e647969214d (git)
Affected: 4ed131d0bb1597ce12fff22d9d7fc9720a6e8cf0 , < aabfc845838ef453f1d22d7665596f9cc48be7dd (git)
Affected: 4ed131d0bb1597ce12fff22d9d7fc9720a6e8cf0 , < 6f83de384ca582fa87b4c2b0d03bd1ed3bf9a2ee (git)
Affected: 4ed131d0bb1597ce12fff22d9d7fc9720a6e8cf0 , < d3ff718c0c7153e2641e6a09507bace14fc5c402 (git)
Affected: 4ed131d0bb1597ce12fff22d9d7fc9720a6e8cf0 , < ef369446f62903ea079e8a7954b5bf8bb8300fe3 (git)
Affected: 4ed131d0bb1597ce12fff22d9d7fc9720a6e8cf0 , < 449ae7927152e46acbe5f19f97eafdae6d3a96b1 (git)
guessed Create a notification for this product.
Linux Linux Affected: 4.16
Unaffected: 0 , < 4.16 (semver)
Unaffected: 6.1.178 , ≤ 6.1.* (semver)
Unaffected: 6.6.145 , ≤ 6.6.* (semver)
Unaffected: 6.12.97 , ≤ 6.12.* (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/infiniband/hw/mlx5/main.c"
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          "vendor": "Linux",
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              "version": "4.16"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
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              "version": "6.6.145",
              "versionType": "semver"
            },
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              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
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              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "4.16",
                  "vulnerable": true
                },
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              "negate": false,
              "operator": "OR"
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      "descriptions": [
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/mlx5: Release the HW\u2011provided UAR index rather than the SW one\n\nFree the UAR index returned by the hardware."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - Exploitation requires a local mmap(2) on an opened mlx5 uverbs file descriptor (/dev/infiniband/uverbs*); the bug is in uar_mmap() error cleanup and is not reachable via remote RDMA/network packet handling.\nAC:L - An attacker who can open uverbs and issue MLX5_IB_MMAP_ALLOC_WC can reliably reach the faulty cleanup by forcing rdma_user_mmap_io()/io_remap_pfn_range() to fail (e.g., memory or VMA map pressure), and controls all syscall parameters for the race-free trigger.\nPR:L - Any unprivileged local user with access to the mlx5 RDMA character device (default 0666 uverbs nodes on shared HPC/cloud compute nodes with ConnectX NICs) can alloc a context and mmap; no real-root or CAP_SYS_ADMIN capability is required.\nUI:N - Exploitation is fully attacker-driven through uverbs open, alloc_ucontext, and mmap syscalls; no victim interaction such as mounting filesystems or opening files is needed.\nS:U - Impact is confined to kernel/driver and RDMA device resource integrity on the host; it does not cross a VM-hypervisor or IOMMU security boundary into a different authority.\nC:H - Deallocating the wrong hardware UAR index frees another context\u0027s live UAR while the attacker-allocated UAR leaks, creating a cross-context UAR use-after-free that can expose other users\u0027 MMIO doorbell/register mappings and device state.\nI:H - UAR pages provide userspace MMIO write access to mlx5 doorbells and control registers; corrupting or reassigning UAR ownership enables arbitrary device register/DMA manipulation and is exploitable for privilege escalation beyond simple data tampering.\nA:H - Freeing an in-use hardware UAR from another context can cause kernel oops/panic, NIC hangs, or repeated crashes when victims continue doorbell/MMIO access through stale mappings."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:45:34.579Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/80f1f49f53a42733e60c90e0ec545e647969214d"
        },
        {
          "url": "https://git.kernel.org/stable/c/aabfc845838ef453f1d22d7665596f9cc48be7dd"
        },
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          "url": "https://git.kernel.org/stable/c/6f83de384ca582fa87b4c2b0d03bd1ed3bf9a2ee"
        },
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          "url": "https://git.kernel.org/stable/c/d3ff718c0c7153e2641e6a09507bace14fc5c402"
        },
        {
          "url": "https://git.kernel.org/stable/c/ef369446f62903ea079e8a7954b5bf8bb8300fe3"
        },
        {
          "url": "https://git.kernel.org/stable/c/449ae7927152e46acbe5f19f97eafdae6d3a96b1"
        }
      ],
      "title": "RDMA/mlx5: Release the HW\u2011provided UAR index rather than the SW one",
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74296",
    "datePublished": "2026-08-15T05:58:00.758Z",
    "dateReserved": "2026-08-15T05:44:03.882Z",
    "dateUpdated": "2026-08-17T05:45:34.579Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "cve": "CVE-2026-74296",
      "date": "2026-09-04",
      "epss": "0.00129",
      "percentile": "0.02885"
    },
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-20T16:22:21+00:00",
      "cve": "CVE-2026-74296",
      "id": "CVE-2026-74296",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: RDMA/mlx5: Release the HW\u0026#8209;provided UAR index rather than the SW one",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74296.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

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.