CVE-2026-93054 (GCVE-0-2026-93054)
Vulnerability from cvelistv5
Published
2026-09-17 16:10
Modified
2026-10-19 09:04
Severity ?
7.0 (High) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: uio: Fix stale info pointer in failed registration path After device_add(), the UIO device is visible to userspace and /dev/uioX can be opened. If a later setup step fails, __uio_register_device() unwinds the device but leaves idev->info pointing at the caller-owned struct uio_info. That is unsafe when an opener races with the failed registration path. The open file keeps a reference to the uio_device, while the caller sees registration failure and may free its struct uio_info. Later file operations can then follow idev->info and dereference freed memory. Handle post-device_add() failures like unregister: remove UIO attributes while the info pointer is still valid, then clear idev->info under info_lock and wake existing waiters/async users before removing the device and minor. This makes already-open file descriptors observe the same "device gone" state as normal uio_unregister_device().
References
Impacted products
Vendor Product Version
Linux Linux Version: a93e7b331568227500186a465fee3c2cb5dffd1f
Version: a93e7b331568227500186a465fee3c2cb5dffd1f
Version: a93e7b331568227500186a465fee3c2cb5dffd1f
Version: a93e7b331568227500186a465fee3c2cb5dffd1f
Version: a93e7b331568227500186a465fee3c2cb5dffd1f
Version: a93e7b331568227500186a465fee3c2cb5dffd1f
Version: a93e7b331568227500186a465fee3c2cb5dffd1f
Version: a93e7b331568227500186a465fee3c2cb5dffd1f
Version: 085d735c858934e5d5bfaedb1fc98bd9135e6ff1
Version: 4.14.100   ≤
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{
  "containers": {
    "cna": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/uio/uio.c"
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          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "version": "4.18"
            },
            {
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              "status": "unaffected",
              "version": "0",
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            },
            {
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              "status": "unaffected",
              "version": "5.10.270",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "5.15.221",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.18.52",
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              "status": "unaffected",
              "version": "7.2.6",
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            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
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        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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                  "versionEndExcluding": "5.10.270",
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                  "vulnerable": true
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                {
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                  "versionEndExcluding": "5.15.221",
                  "versionStartIncluding": "4.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.188",
                  "versionStartIncluding": "4.18",
                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.157",
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                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "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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                  "versionStartIncluding": "4.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
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                },
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              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nuio: Fix stale info pointer in failed registration path\n\nAfter device_add(), the UIO device is visible to userspace and /dev/uioX\ncan be opened. If a later setup step fails, __uio_register_device()\nunwinds the device but leaves idev-\u003einfo pointing at the caller-owned\nstruct uio_info.\n\nThat is unsafe when an opener races with the failed registration path.\nThe open file keeps a reference to the uio_device, while the caller sees\nregistration failure and may free its struct uio_info. Later file\noperations can then follow idev-\u003einfo and dereference freed memory.\n\nHandle post-device_add() failures like unregister: remove UIO attributes\nwhile the info pointer is still valid, then clear idev-\u003einfo under\ninfo_lock and wake existing waiters/async users before removing the\ndevice and minor. This makes already-open file descriptors observe the\nsame \"device gone\" state as normal uio_unregister_device()."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - After device_add() in __uio_register_device(), the char device is opened via open(2) on /dev/uioN into uio_open(); the dangling idev-\u003einfo is then used by uio_write/uio_mmap/uio_release on that fd. Callers such as tcmu_configure_device() (configfs enable) and uio_pci_generic probe() register locally; no remote protocol carries the trigger.\nAC:H - The stale-info unwind runs only when uio_dev_add_attributes() (kobject_create_and_add/kobject_add/kobject_uevent for maps/portio) or request_threaded_irq() fails after device_add(). Those fail on -ENOMEM, kernfs errors, or IRQ setup failure the attacker cannot force; a successful register never leaves idev-\u003einfo set after the caller drops struct uio_info.\nPR:L - uio_open() has no capable() check, and uio_pci_generic installs no info-\u003eopen hook, so the racing open is gated only by /dev/uioN inode mode. Reasonable UIO deployments (DPDK udev, tcmu-runner) grant that node to a non-root account that can also write target_dev_enable_store (TCMU) or hold the fd across a failing probe.\nUI:N - The same actor can write target_dev_enable_store (echo 1 \u003e enable -\u003e tcmu_configure_device -\u003e uio_register_device) or bind uio_pci_generic while another thread open()s /dev/uioN and then mmap/write/close; no other user must mount media or confirm a prompt.\nS:U - The use-after-free is idev-\u003einfo in the host UIO core (uio_write/uio_mmap/uio_release) after the caller (e.g. devm unwind of uio_pci_generic\u0027s struct uio_pci_generic_dev) frees struct uio_info; impact stays in the host kernel, not a KVM/Xen, IOMMU, or sandbox escape.\nC:H - After the caller frees struct uio_info, uio_read and uio_mmap still treat the non-NULL idev-\u003einfo as live and read info-\u003eirq, info-\u003emem[], and related fields. Reclaiming that slab object gives an arbitrary kernel read through those file operations.\nI:H - uio_write() calls idev-\u003einfo-\u003eirqcontrol, uio_open() calls info-\u003eopen, and uio_release() calls info-\u003erelease on the freed uio_info; uio_mmap_physical() feeds info-\u003emem[].addr into remap_pfn_range(). Spraying the object hijacks those function pointers or the PFN map for an arbitrary write/CFI primitive.\nA:H - uio_write/uio_mmap/uio_release and uio_vma_fault dereference the freed idev-\u003einfo (and TCMU\u0027s tcmu_vma_fault uses info-\u003emem[].addr after vfree(mb_addr) on err_register), which oopses or panics the kernel even without a successful spray."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:04:49.183Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/63eaa7663335d482a8825c231213e312cacea567"
        },
        {
          "url": "https://git.kernel.org/stable/c/df4faf65194ec6c315a59be4c6749eaeb3009243"
        },
        {
          "url": "https://git.kernel.org/stable/c/506b43dde5f9ac0068b1360e6b5dbee07fda59fb"
        },
        {
          "url": "https://git.kernel.org/stable/c/15340b00e665af805523b08515294a1aa1778151"
        },
        {
          "url": "https://git.kernel.org/stable/c/234156f6c6d9ec35dc47abbcc3adc3c79fc6a5ac"
        },
        {
          "url": "https://git.kernel.org/stable/c/16695e9059d80ea6661e8399064b0c01f641dd8c"
        },
        {
          "url": "https://git.kernel.org/stable/c/ec5bd6731183eb6f619140c9bef2ee11ed818c20"
        },
        {
          "url": "https://git.kernel.org/stable/c/67b6fc084b034a91c3ec7907a3fed89a2450f30b"
        }
      ],
      "title": "uio: Fix stale info pointer in failed registration path",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-93054",
    "datePublished": "2026-09-17T16:10:43.104Z",
    "dateReserved": "2026-09-17T15:57:05.658Z",
    "dateUpdated": "2026-10-19T09:04:49.183Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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