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CVE-2026-74396 (GCVE-0-2026-74396)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:59 – Updated: 2026-08-17 05:46
VLAI
Title
RDMA/mlx5: Fix UMR XLT cleanup on ODP populate failure
Summary
In the Linux kernel, the following vulnerability has been resolved: RDMA/mlx5: Fix UMR XLT cleanup on ODP populate failure mlx5r_umr_update_xlt() allocates and DMA maps an XLT buffer with mlx5r_umr_create_xlt(). The buffer is released by the common cleanup path through mlx5r_umr_unmap_free_xlt(). After mlx5_odp_populate_xlt() became fallible, its error path returned directly and skipped that cleanup. This leaks the XLT DMA mapping and buffer. If the emergency XLT page was used, it also leaves xlt_emergency_page_mutex locked. Break out of the loop so execution falls through the existing cleanup path.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 1efe8c0670d6a6883faa09c9abc746c741f5664a , < ffa85a2c197935ace6f1634ad9eb0a44bc615670 (git)
Affected: 1efe8c0670d6a6883faa09c9abc746c741f5664a , < 9619909d4869afe720904c6888a289b9ac3055b8 (git)
Affected: 1efe8c0670d6a6883faa09c9abc746c741f5664a , < 1eae35b37923cb71b0cb5136d00671440d488b9f (git)
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Linux Linux Affected: 6.16
Unaffected: 0 , < 6.16 (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
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          "product": "Linux",
          "programFiles": [
            "drivers/infiniband/hw/mlx5/umr.c"
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/mlx5: Fix UMR XLT cleanup on ODP populate failure\n\nmlx5r_umr_update_xlt() allocates and DMA maps an XLT buffer with\nmlx5r_umr_create_xlt(). The buffer is released by the common cleanup path\nthrough mlx5r_umr_unmap_free_xlt().\n\nAfter mlx5_odp_populate_xlt() became fallible, its error path returned\ndirectly and skipped that cleanup. This leaks the XLT DMA mapping and\nbuffer. If the emergency XLT page was used, it also leaves\nxlt_emergency_page_mutex locked.\n\nBreak out of the loop so execution falls through the existing cleanup path."
        }
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            "version": "3.1"
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              "lang": "en",
              "value": "AV:N - Remote RDMA peers trigger mlx5 ODP hardware page faults over RoCE/InfiniBand (mlx5_ib_mr_rdma_pfault_handler \u2192 pagefault_real_mr \u2192 mlx5r_umr_update_xlt), reaching the buggy cleanup on mlx5 AI/HPC/cloud servers without local syscalls.\nAC:L - An attacker can repeatedly drive ODP page faults, exhaust memory to force the emergency XLT page path, and retry until mlx5_odp_populate_xlt()/hmm_dma_map_pfn() fails; no uncontrollable race or memory layout is required.\nPR:N - The RDMA responder page-fault path executes in kernel workqueues on packets from a connected remote peer and performs no Linux capability or credential check before calling mlx5r_umr_update_xlt().\nUI:N - Exploitation requires only attacker-generated RDMA traffic against exported ODP memory regions once a queue pair exists; no additional victim action beyond normal RDMA service operation is needed.\nS:U - The DMA mapping leak and permanent xlt_emergency_page_mutex lock affect mlx5 driver resources within the same host kernel security authority; there is no VM escape or IOMMU-boundary bypass.\nC:N - The bug skips unmap/free of an XLT translation buffer; it does not corrupt memory, dereference freed objects, or provide an arbitrary kernel read primitive.\nI:N - No out-of-bounds write, use-after-free, or control-flow corruption occurs; the defect only leaks resources rather than enabling arbitrary data modification.\nA:H - Each failure leaks a DMA mapping and buffer, and on the emergency-page path permanently locks xlt_emergency_page_mutex, deadlocking subsequent UMR XLT updates and disabling ODP/RDMA on the mlx5 device."
            }
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        }
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        },
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          "url": "https://git.kernel.org/stable/c/1eae35b37923cb71b0cb5136d00671440d488b9f"
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    "cveId": "CVE-2026-74396",
    "datePublished": "2026-08-15T05:59:08.694Z",
    "dateReserved": "2026-08-15T05:44:03.891Z",
    "dateUpdated": "2026-08-17T05:46:40.931Z",
    "state": "PUBLISHED"
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    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-08-20T22:20:12+00:00",
      "cve": "CVE-2026-74396",
      "id": "CVE-2026-74396",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "184",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: RDMA/mlx5: Fix UMR XLT cleanup on ODP populate failure",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74396.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.