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CVE-2026-74274 (GCVE-0-2026-74274)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:57 – Updated: 2026-08-17 05:16
VLAI
Title
cxl/region: Fill first free targets[] slot during auto-discovery
Summary
In the Linux kernel, the following vulnerability has been resolved: cxl/region: Fill first free targets[] slot during auto-discovery Any invalid endpoint decoder pointer in the target array of an active region is not allowed by cxl driver. This means cxl driver always assumes the first p->nr_targets entries of the target array in an auto-assembly region are valid. However, there are scenarios that could leave NULL endpoint decoder pointer holes in the target array. 1. When cxl_cancel_auto_attach() removes an endpoint decoder from a target array, the target slot is set to NULL. If the removed endpoint decoder is not the last element in the target array, the target array will contain a NULL hole. 2. When a auto-assembly region removes an assigned endpoint decoder, if the removed endpoint decoder is not the last element in the target array, always remains a NULL hole in the target array. When a NULL pointer hole exists in a region's target array, it introduces two potential problems: 1. Access an endpoint decoder via a NULL pointer. it always trigger calltrace like that. Oops: general protection fault, probably for non-canonical address 0xdffffc0000000008: 0000 [#1] SMP KASAN PTI RIP: 0010:cxl_calc_interleave_pos+0x26/0x810 [cxl_core] Call Trace: <TASK> cxl_region_attach+0xc50/0x2140 [cxl_core] cxl_add_to_region+0x321/0x2330 [cxl_core] discover_region+0x92/0x150 [cxl_port] device_for_each_child+0xf3/0x170 cxl_port_probe+0x150/0x200 [cxl_port] cxl_bus_probe+0x4f/0xa0 [cxl_core] really_probe+0x1c8/0x960 __driver_probe_device+0x323/0x450 driver_probe_device+0x45/0x120 __device_attach_driver+0x15d/0x280 bus_for_each_drv+0x10f/0x190 2. Not having enough valid endpoint decoders attached to an auto-assembly region. if an auto-assembly region is created with lock flag or assigned endpoint decoder with lock flag, which means assigned endpoint decoder will not be reset during detaching, they could re-attach to the auto-assembly region again. But cxl region driver relies on p->nr_targets to verify whether the required number of endpoint decoders has been attached, and NULL endpoint decoder pointers are still counted in that case. To fix above issues, adjust cxl_region_attach_auto() logic to find the first free target slot for endpoint decoder attachment, this ensures NULL holes in the target array are filled, rather than adding new endpoint decoders at the tail of the target array.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 2230c4bdc4120417799c74326ade3123da226d54 , < 6fde3fcdfec438ba0df26e25a8ac7c3707211799 (git)
Affected: 2230c4bdc4120417799c74326ade3123da226d54 , < aa8a76711c15041ec1e42c3a74c15c2df0bd31f6 (git)
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Linux Linux Affected: 6.19
Unaffected: 0 , < 6.19 (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/cxl/core/region.c"
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncxl/region: Fill first free targets[] slot during auto-discovery\n\nAny invalid endpoint decoder pointer in the target array of an active\nregion is not allowed by cxl driver. This means cxl driver always\nassumes the first p-\u003enr_targets entries of the target array in an\nauto-assembly region are valid. However, there are scenarios that could\nleave NULL endpoint decoder pointer holes in the target array.\n\n1. When cxl_cancel_auto_attach() removes an endpoint decoder from a\n   target array, the target slot is set to NULL. If the removed endpoint\n   decoder is not the last element in the target array, the target array\n   will contain a NULL hole.\n\n2. When a auto-assembly region removes an assigned endpoint decoder, if\n   the removed endpoint decoder is not the last element in the target\n   array, always remains a NULL hole in the target array.\n\nWhen a NULL pointer hole exists in a region\u0027s target array, it\nintroduces two potential problems:\n1. Access an endpoint decoder via a NULL pointer. it always trigger\n   calltrace like that.\n    Oops: general protection fault, probably for non-canonical address 0xdffffc0000000008: 0000 [#1] SMP KASAN PTI\n    RIP: 0010:cxl_calc_interleave_pos+0x26/0x810 [cxl_core]\n    Call Trace:\n      \u003cTASK\u003e\n      cxl_region_attach+0xc50/0x2140 [cxl_core]\n      cxl_add_to_region+0x321/0x2330 [cxl_core]\n      discover_region+0x92/0x150 [cxl_port]\n      device_for_each_child+0xf3/0x170\n      cxl_port_probe+0x150/0x200 [cxl_port]\n      cxl_bus_probe+0x4f/0xa0 [cxl_core]\n      really_probe+0x1c8/0x960\n      __driver_probe_device+0x323/0x450\n      driver_probe_device+0x45/0x120\n      __device_attach_driver+0x15d/0x280\n      bus_for_each_drv+0x10f/0x190\n\n2. Not having enough valid endpoint decoders attached to an\n   auto-assembly region. if an auto-assembly region is created with lock\n   flag or assigned endpoint decoder with lock flag, which means\n   assigned endpoint decoder will not be reset during detaching, they\n   could re-attach to the auto-assembly region again. But cxl region\n   driver relies on p-\u003enr_targets to verify whether the required number\n   of endpoint decoders has been attached, and NULL endpoint decoder\n   pointers are still counted in that case.\n\nTo fix above issues, adjust cxl_region_attach_auto() logic to find the\nfirst free target slot for endpoint decoder attachment, this ensures\nNULL holes in the target array are filled, rather than adding new\nendpoint decoders at the tail of the target array."
        }
      ],
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        "dateUpdated": "2026-08-17T05:16:18.253Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/6fde3fcdfec438ba0df26e25a8ac7c3707211799"
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        {
          "url": "https://git.kernel.org/stable/c/aa8a76711c15041ec1e42c3a74c15c2df0bd31f6"
        }
      ],
      "title": "cxl/region: Fill first free targets[] slot during auto-discovery",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74274",
    "datePublished": "2026-08-15T05:57:46.798Z",
    "dateReserved": "2026-08-15T05:44:03.879Z",
    "dateUpdated": "2026-08-17T05:16:18.253Z",
    "state": "PUBLISHED"
  },
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    "epss": {
      "cve": "CVE-2026-74274",
      "date": "2026-09-05",
      "epss": "0.00173",
      "percentile": "0.06825"
    },
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    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-08-20T15:22:28+00:00",
      "cve": "CVE-2026-74274",
      "id": "CVE-2026-74274",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: cxl/region: Fill first free targets[] slot during auto-discovery",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74274.json",
      "version": "3"
    }
  }
}



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