CVE-2026-72095 (GCVE-0-2026-72095)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:52 – Updated: 2026-08-17 05:40
VLAI
Title
dma-fence: Make dma_fence_dedup_array() robust against 0-count input
Summary
In the Linux kernel, the following vulnerability has been resolved: dma-fence: Make dma_fence_dedup_array() robust against 0-count input dma_fence_dedup_array() returns 1 when called with num_fences == 0: the for-loop body never executes, j stays at 0, and the final `return ++j` yields 1. This contradicts both the kernel-doc ("Return: Number of unique fences remaining in the array") and the natural expectation that 0 input gives 0 output. The caller __dma_fence_unwrap_merge() bails out via the `if (count == 0 || count == 1)` fast path and so is save. But amdgpu_userq_wait_*() could reach the dedup call with a zero local count and dereference an uninitialized fence slot in the array. Make the contract match the documentation by returning 0 early. This also skips an unnecessary sort() call on an empty array.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 575ec9b0c2f11f40535ea737ed5a64792780d1ef , < 7aa8f3dba53422465dbe1be8dbb7240304462bb2 (git)
Affected: 575ec9b0c2f11f40535ea737ed5a64792780d1ef , < e2d9a2ea178a5da0b4a6693e8ebca5c7fc4d7051 (git)
Affected: 575ec9b0c2f11f40535ea737ed5a64792780d1ef , < 77a9298741f8f9e8b963c977f5582ab21c6d3427 (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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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/dma-buf/dma-fence-unwrap.c"
          ],
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          "vendor": "Linux",
          "versions": [
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              "versionType": "git"
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          "vendor": "Linux",
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              "versionType": "semver"
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              "version": "7.1.5",
              "versionType": "semver"
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              "operator": "OR"
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndma-fence: Make dma_fence_dedup_array() robust against 0-count input\n\ndma_fence_dedup_array() returns 1 when called with num_fences == 0:\nthe for-loop body never executes, j stays at 0, and the final\n`return ++j` yields 1. This contradicts both the kernel-doc (\"Return:\nNumber of unique fences remaining in the array\") and the natural\nexpectation that 0 input gives 0 output.\n\nThe caller __dma_fence_unwrap_merge() bails out via the\n`if (count == 0 || count == 1)` fast path and so is save.\n\nBut amdgpu_userq_wait_*() could reach the dedup call with a zero local\ncount and dereference an uninitialized fence slot in the array.\n\nMake the contract match the documentation by returning 0 early. This\nalso skips an unnecessary sort() call on an empty array."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
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            "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 bug is reached only via the AMDGPU_USERQ_WAIT DRM ioctl on /dev/dri/renderD*, requiring local access to an AMD GPU render node; it is not reachable from network protocols or remote packet handling.\nAC:L - An attacker with render-node access can reliably trigger the bug by creating a userq, calling AMDGPU_USERQ_WAIT with num_fences\u003e0 and zero syncobj/BO handles so local num_fences stays 0 and dma_fence_dedup_array() incorrectly returns 1.\nPR:L - Exploitation requires only an authenticated DRM client on a render node (DRM_AUTH|DRM_RENDER_ALLOW), which unprivileged users commonly obtain via the render group on workstations, cloud GPU instances, and shared compute nodes.\nUI:N - No victim interaction is required; the attacker drives the vulnerable AMDGPU_USERQ_WAIT ioctl directly after creating their own user queue.\nS:U - Impact remains within the host kernel security domain (local privilege escalation/DoS on the GPU server); it does not cross VM, container, or IOMMU boundaries.\nC:H - When num_fences is 0 the dedup helper returns 1, causing iteration over uninitialized kmalloc slots whose stale contents are then dereferenced via to_amdgpu_userq_fence()/dma_fence_wait(), enabling kernel memory reads and pointer disclosure.\nI:H - The uninitialized fences[0] pointer is passed into dma_fence_enable_sw_signaling() and dma_fence_wait(), which invoke fence ops and locking on attacker-influenced addresses, creating a plausible path to control-flow hijacking via heap grooming.\nA:H - Dereferencing an uninitialized or attacker-influenced dma_fence pointer in kernel context can cause an oops, BUG, or panic, producing a repeatable local denial of service on affected AMDGPU userq systems."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:40:12.383Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/7aa8f3dba53422465dbe1be8dbb7240304462bb2"
        },
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          "url": "https://git.kernel.org/stable/c/e2d9a2ea178a5da0b4a6693e8ebca5c7fc4d7051"
        },
        {
          "url": "https://git.kernel.org/stable/c/77a9298741f8f9e8b963c977f5582ab21c6d3427"
        }
      ],
      "title": "dma-fence: Make dma_fence_dedup_array() robust against 0-count input",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72095",
    "datePublished": "2026-08-15T05:52:41.470Z",
    "dateReserved": "2026-08-09T03:40:39.905Z",
    "dateUpdated": "2026-08-17T05:40:12.383Z",
    "state": "PUBLISHED"
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      "date": "2026-09-21",
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      "percentile": "0.05757"
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                ],
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        "cveTags": [],
        "descriptions": [
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndma-fence: Make dma_fence_dedup_array() robust against 0-count input\n\ndma_fence_dedup_array() returns 1 when called with num_fences == 0:\nthe for-loop body never executes, j stays at 0, and the final\n`return ++j` yields 1. This contradicts both the kernel-doc (\"Return:\nNumber of unique fences remaining in the array\") and the natural\nexpectation that 0 input gives 0 output.\n\nThe caller __dma_fence_unwrap_merge() bails out via the\n`if (count == 0 || count == 1)` fast path and so is save.\n\nBut amdgpu_userq_wait_*() could reach the dedup call with a zero local\ncount and dereference an uninitialized fence slot in the array.\n\nMake the contract match the documentation by returning 0 early. This\nalso skips an unnecessary sort() call on an empty array."
          }
        ],
        "id": "CVE-2026-72095",
        "lastModified": "2026-08-17T06:18:08.397",
        "metrics": {
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            {
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                "attackVector": "LOCAL",
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                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
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              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        "vulnStatus": "Received"
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      "current_release_date": "2026-08-17T21:48:33+00:00",
      "cve": "CVE-2026-72095",
      "id": "CVE-2026-72095",
      "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: dma-fence: Make dma_fence_dedup_array() robust against 0-count input",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72095.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-08-28T16:40:55Z",
      "cve": "CVE-2026-72095",
      "id": "CVE-2026-72095",
      "initial_release_date": "2026-08-28T16:40:55Z",
      "product_status:known_not_affected": "362",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-72095",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-72095.json",
      "version": "2"
    }
  }
}



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  • 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.
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