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CVE-2026-89940 (GCVE-0-2026-89940)

Vulnerability from cvelistv5 – Published: 2026-09-16 10:32 – Updated: 2026-09-16 14:40
VLAI
Title
iio: buffer: Tie IIO dma fence lock lifetime to the fence
Summary
In the Linux kernel, the following vulnerability has been resolved: iio: buffer: Tie IIO dma fence lock lifetime to the fence The `iio_dma_fence` implementation currently uses a lock embedded in the `iio_dmabuf_priv`. But the `iio_dma_fence` can outlive the `iio_dmabuf_priv`, which can cause a use-after-free. Tie the lifetime of the lock to the lifetime of the fence by embedding them in the same struct. We can't just hold a reference to the `iio_dmabuf_priv` from the `iio_dma_fence` since `iio_buffer_dmabuf_release()` might sleep and the fence release callback is not allowed to sleep. Note that the `dma_fence` framework now has an internal lock that gets used when the passing `NULL` for `lock` in `dma_fence_init()`, but in order to allow this patch to be backportable use an external lock.
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f , < 6865d79fca17a80fbd60c12550ca9a5e0e20e0eb (git)
Affected: 3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f , < 510497e31be4f241103507315a859e2085ccb081 (git)
Affected: 3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f , < 8b3e221590181a8beb3735bbabf166df02c839b5 (git)
Affected: 3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f , < f25ec4627d935dedfb5fe83bd2c2678cdcc19611 (git)
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Linux Linux Affected: 6.11
Unaffected: 0 , < 6.11 (semver)
Unaffected: 6.12.110 , ≤ 6.12.* (semver)
Unaffected: 6.18.51 , ≤ 6.18.* (semver)
Unaffected: 7.2.5 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)
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Show details on NVD website

{
  "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"
            },
            {
              "lessThan": "510497e31be4f241103507315a859e2085ccb081",
              "status": "affected",
              "version": "3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f",
              "versionType": "git"
            },
            {
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              "status": "affected",
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              "versionType": "git"
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              "status": "affected",
              "version": "3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f",
              "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"
            },
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              "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-rc1",
              "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-rc1",
                  "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: Tie IIO dma fence lock lifetime to the fence\n\nThe `iio_dma_fence` implementation currently uses a lock embedded in the\n`iio_dmabuf_priv`. But the `iio_dma_fence` can outlive the\n`iio_dmabuf_priv`, which can cause a use-after-free.\n\nTie the lifetime of the lock to the lifetime of the fence by embedding them\nin the same struct.\n\nWe can\u0027t just hold a reference to the `iio_dmabuf_priv` from the\n`iio_dma_fence` since `iio_buffer_dmabuf_release()` might sleep and the\nfence release callback is not allowed to sleep.\n\nNote that the `dma_fence` framework now has an internal lock that gets used\nwhen the passing `NULL` for `lock` in `dma_fence_init()`, but in order to\nallow this patch to be backportable use an external lock."
        }
      ],
      "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 through local IIO_BUFFER_DMABUF_ATTACH/ENQUEUE/DETACH ioctls on an anonymous iio:buffer fd from IIO_BUFFER_GET_FD_IOCTL on /dev/iio:deviceN; it is not reachable from network packet processing or adjacent-link protocols.\nAC:L - The attacker fully controls the lifetime mismatch: they attach and enqueue a DMA-BUF so the dma_fence lock lives in iio_dmabuf_priv, then detach so priv is freed while the fence remains in the DMA-BUF reservation, and later DMA_BUF_IOCTL_SYNC/wait takes that freed lock.\nPR:L - The IIO open and ioctl path has no capability check, only filesystem access to the device node. On Android phones, industrial converters, and embedded systems exposing this DMA-BUF buffer API, /dev/iio:device* is commonly group-accessible without init-namespace root.\nUI:N - The attacker opens the IIO device, issues the DMA-BUF attach/enqueue/detach ioctls, and waits on their own DMA-BUF file descriptor; no separate victim action is required.\nS:U - This is a standard in-kernel heap use-after-free of iio_dmabuf_priv within the host kernel\u0027s security authority, not a VM escape, IOMMU boundary bypass, or sandbox escape.\nC:H - The dma_fence retains a pointer to a spinlock embedded in freed iio_dmabuf_priv; later fence wait/sync operations use that lock, a slab use-after-free that can be turned into an arbitrary kernel memory read via heap spraying.\nI:H - The same use-after-free of iio_dmabuf_priv lets an attacker reclaim the object and corrupt dma_fence lock and callback state during later wait or signaling paths, enabling heap corruption, arbitrary write, and control-flow hijacking.\nA:H - Taking a spinlock in already-freed iio_dmabuf_priv memory causes a kernel oops, BUG, or panic; any use-after-free is high availability impact even when not fully exploited."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-16T14:40:26.549Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/6865d79fca17a80fbd60c12550ca9a5e0e20e0eb"
        },
        {
          "url": "https://git.kernel.org/stable/c/510497e31be4f241103507315a859e2085ccb081"
        },
        {
          "url": "https://git.kernel.org/stable/c/8b3e221590181a8beb3735bbabf166df02c839b5"
        },
        {
          "url": "https://git.kernel.org/stable/c/f25ec4627d935dedfb5fe83bd2c2678cdcc19611"
        }
      ],
      "title": "iio: buffer: Tie IIO dma fence lock lifetime to the fence",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89940",
    "datePublished": "2026-09-16T10:32:28.395Z",
    "dateReserved": "2026-09-11T19:38:34.776Z",
    "dateUpdated": "2026-09-16T14:40:26.549Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-89940\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-09-16T11:17:03.610\",\"lastModified\":\"2026-09-16T15:18:19.340\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\niio: buffer: Tie IIO dma fence lock lifetime to the fence\\n\\nThe `iio_dma_fence` implementation currently uses a lock embedded in the\\n`iio_dmabuf_priv`. But the `iio_dma_fence` can outlive the\\n`iio_dmabuf_priv`, which can cause a use-after-free.\\n\\nTie the lifetime of the lock to the lifetime of the fence by embedding them\\nin the same struct.\\n\\nWe can\u0027t just hold a reference to the `iio_dmabuf_priv` from the\\n`iio_dma_fence` since `iio_buffer_dmabuf_release()` might sleep and the\\nfence release callback is not allowed to sleep.\\n\\nNote that the `dma_fence` framework now has an internal lock that gets used\\nwhen the passing `NULL` for `lock` in `dma_fence_init()`, but in order to\\nallow this patch to be backportable use an external lock.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"drivers/iio/industrialio-buffer.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f\",\"lessThan\":\"6865d79fca17a80fbd60c12550ca9a5e0e20e0eb\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f\",\"lessThan\":\"510497e31be4f241103507315a859e2085ccb081\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f\",\"lessThan\":\"8b3e221590181a8beb3735bbabf166df02c839b5\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f\",\"lessThan\":\"f25ec4627d935dedfb5fe83bd2c2678cdcc19611\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"drivers/iio/industrialio-buffer.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.11\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.11\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.110\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.51\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2.5\",\"lessThanOrEqual\":\"7.2.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.3-rc1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/510497e31be4f241103507315a859e2085ccb081\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/6865d79fca17a80fbd60c12550ca9a5e0e20e0eb\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/8b3e221590181a8beb3735bbabf166df02c839b5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f25ec4627d935dedfb5fe83bd2c2678cdcc19611\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}



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