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GHSA-CGWR-M873-G7W9

Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-17 06:33

Details

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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-72095"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T06:21:23Z",
    "severity": "HIGH"
  },
  "details": "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": "GHSA-cgwr-m873-g7w9",
  "modified": "2026-08-17T06:33:09Z",
  "published": "2026-08-15T06:32:11Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72095"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/77a9298741f8f9e8b963c977f5582ab21c6d3427"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7aa8f3dba53422465dbe1be8dbb7240304462bb2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e2d9a2ea178a5da0b4a6693e8ebca5c7fc4d7051"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

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

Vulnerability from cvelistv5 – Published: 2026-08-15 05:52 – Updated: 2026-08-17 05:40

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

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/7aa8f3dba53422465…
https://git.kernel.org/stable/c/e2d9a2ea178a5da0b…
https://git.kernel.org/stable/c/77a9298741f8f9e8b…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 575ec9b0c2f11f40535ea737ed5a64792780d1ef , < 7aa8f3dba53422465dbe1be8dbb7240304462bb2 (git) Affected: 575ec9b0c2f11f40535ea737ed5a64792780d1ef , < e2d9a2ea178a5da0b4a6693e8ebca5c7fc4d7051 (git) Affected: 575ec9b0c2f11f40535ea737ed5a64792780d1ef , < 77a9298741f8f9e8b963c977f5582ab21c6d3427 (git)
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"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "lessThan": "7aa8f3dba53422465dbe1be8dbb7240304462bb2",
              "status": "affected",
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            },
            {
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              "status": "affected",
              "version": "575ec9b0c2f11f40535ea737ed5a64792780d1ef",
              "versionType": "git"
            },
            {
              "lessThan": "77a9298741f8f9e8b963c977f5582ab21c6d3427",
              "status": "affected",
              "version": "575ec9b0c2f11f40535ea737ed5a64792780d1ef",
              "versionType": "git"
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          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "versionStartIncluding": "6.16",
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                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "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."
        }
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      "metrics": [
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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/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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        "engine": "bippy-1.2.0"
      }
    }
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    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "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"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
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.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

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GHSA-CGWR-M873-G7W9

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

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Nomenclature