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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{
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          "programFiles": [
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              "versionType": "semver"
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              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
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      ],
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          "nodes": [
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                  "versionStartIncluding": "4.16",
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              "operator": "OR"
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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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        },
        {
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      "title": "RDMA/mlx5: Release the HW\u2011provided UAR index rather than the SW one",
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    "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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          }
        ],
        "id": "CVE-2026-74296",
        "lastModified": "2026-08-17T06:19:23.680",
        "metrics": {
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                "attackVector": "LOCAL",
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                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        "vulnStatus": "Received"
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    },
    "redhat_vex": {
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      "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"
    },
    "suse_vex": {
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      "current_release_date": "2026-09-23T00:18:25Z",
      "cve": "CVE-2026-74296",
      "id": "CVE-2026-74296",
      "initial_release_date": "2026-08-26T01:13:39Z",
      "product_status:first_fixed": "68",
      "product_status:known_affected": "647",
      "product_status:known_not_affected": "18",
      "product_status:recommended": "130",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-74296",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-74296.json",
      "version": "11"
    }
  }
}



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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.



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.