CVE-2026-89941 (GCVE-0-2026-89941)
Vulnerability from cvelistv5
Published
2026-09-16 10:32
Modified
2026-10-19 08:55
Severity ?
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: iio: buffer: Make IIO DMA fence release RCU-safe The `dma_fence` documentation states that if a custom release implementation is provided, the `dma_fence` object must be freed in an RCU-safe way. The current `iio_dma_fence` implementation uses `kfree()`, which might result in a use-after-free. Remove the custom `release` implementation. This makes the DMA fence core fall back to `dma_fence_free()`, which calls `kfree_rcu()` on the fence. This requires that the fence be the first member of `struct iio_dma_fence`. Using the default release method for extended DMA fence structures is a common pattern.
References
Impacted products
Vendor Product Version
Linux Linux Version: 3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f
Version: 3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f
Version: 3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f
Version: 3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/iio/industrialio-buffer.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f",
              "versionType": "git"
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            {
              "lessThan": "06a9460b8b792e109cbc934a856d02e5cff217ef",
              "status": "affected",
              "version": "3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f",
              "versionType": "git"
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              "status": "affected",
              "version": "3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f",
              "versionType": "git"
            },
            {
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              "status": "affected",
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/iio/industrialio-buffer.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.11"
            },
            {
              "lessThan": "6.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.110",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.51",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.5",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\niio: buffer: Make IIO DMA fence release RCU-safe\n\nThe `dma_fence` documentation states that if a custom release\nimplementation is provided, the `dma_fence` object must be freed in an\nRCU-safe way. The current `iio_dma_fence` implementation uses `kfree()`,\nwhich might result in a use-after-free.\n\nRemove the custom `release` implementation. This makes the DMA fence core\nfall back to `dma_fence_free()`, which calls `kfree_rcu()` on the fence.\nThis requires that the fence be the first member of `struct iio_dma_fence`.\n\nUsing the default release method for extended DMA fence structures is a\ncommon pattern."
        }
      ],
      "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 - The use-after-free is reached only through local IIO character-device ioctls (IIO_BUFFER_GET_FD_IOCTL then IIO_BUFFER_DMABUF_ATTACH/ENQUEUE_IOCTL on /dev/iio:deviceN); there is no network, Bluetooth, or USB packet path into the IIO DMA fence release.\nAC:L - The attacker controls both sides of the race by enqueueing IIO DMA-BUF transfers that create and later kfree() the fence while concurrently waiting on or exporting the same dma-buf\u0027s reservation fences via DMA_BUF_IOCTL_SYNC/EXPORT_SYNC_FILE, so the missing RCU grace period is attacker-driven.\nPR:L - The IIO open and ioctl path performs no capability check; only filesystem access to /dev/iio:deviceN is required. On Android, automotive, and industrial/SDR systems that ship DMA-capable IIO converters, that node is commonly group-accessible to unprivileged sensor or application users.\nUI:N - The attacker opens the IIO device, attaches their own DMA-BUF, and issues enqueue and dma-buf sync/export ioctls themselves; no separate victim action is required.\nS:U - The freed iio_dma_fence lives in the host kernel heap and any resulting corruption stays within the same kernel security authority; this is not a VM escape or IOMMU/DMA boundary bypass.\nC:H - Immediate kfree() of the dma_fence lets concurrent dma_resv RCU walkers (dma_fence_get_rcu, dma_fence_driver_name) read the reclaimed slab object; per kernel scoring guidance a use-after-free is High confidentiality impact.\nI:H - The freed dma_fence contains ops function pointers, callback lists, and a spinlock used after free; reclaiming the object with attacker-controlled data yields write and control-flow hijack primitives, so integrity impact is High.\nA:H - Use-after-free of the fence from dma_fence_release or dma_resv iteration causes a kernel oops or panic even without a full exploit, so availability impact is High."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:55:15.605Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/311595dc0b5621f74d8eb4dc38ef4efcdfe7e769"
        },
        {
          "url": "https://git.kernel.org/stable/c/06a9460b8b792e109cbc934a856d02e5cff217ef"
        },
        {
          "url": "https://git.kernel.org/stable/c/11cef99491117d4264603df159c4ff5f3845a059"
        },
        {
          "url": "https://git.kernel.org/stable/c/8662e56c31cf23b61ca3d11b516efb94c35b8026"
        }
      ],
      "title": "iio: buffer: Make IIO DMA fence release RCU-safe",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89941",
    "datePublished": "2026-09-16T10:32:29.148Z",
    "dateReserved": "2026-09-11T19:38:34.777Z",
    "dateUpdated": "2026-10-19T08:55:15.605Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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