CVE-2026-89885 (GCVE-0-2026-89885)
Vulnerability from cvelistv5
Published
2026-09-16 10:31
Modified
2026-10-19 08:54
Severity ?
8.4 (High) - CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: media: platform: mtk-mdp3: Fix SCP device refcounting mdp_probe() first tries to get the SCP handle with scp_get(). When that fails, it falls back to looking up the SCP platform device with __get_pdev_by_id() and then reads its driver data. The fallback lookup returns the platform device with a reference, just like scp_get() does. However, the fallback path currently drops that reference immediately after platform_get_drvdata(). The driver later still calls scp_put(mdp->scp) unconditionally from the probe error path and from mdp_video_device_release(), which drops the SCP device reference again. Keep the fallback reference until the existing scp_put() call, so that the fallback path follows the same ownership rules as the scp_get() path.
References
Impacted products
Vendor Product Version
Linux Linux Version: db4d27e6bbbf511f9cdb33f682535a0a3cb7c403
Version: 31ba1a4d7a5d9466f6ef4910a372b8200f8aad19
Version: 8f6f3aa21517ef34d50808af0c572e69580dca20
Version: 8f6f3aa21517ef34d50808af0c572e69580dca20
Version: 6.12.64   ≤
Version: 6.18.4   ≤
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/media/platform/mediatek/mdp3/mtk-mdp3-core.c"
          ],
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              "status": "affected",
              "version": "6.12.64",
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            },
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            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/media/platform/mediatek/mdp3/mtk-mdp3-core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.19"
            },
            {
              "lessThan": "6.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
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              "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": "6.12.64",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.51",
                  "versionStartIncluding": "6.18.4",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.5",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
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                {
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                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.19",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmedia: platform: mtk-mdp3: Fix SCP device refcounting\n\nmdp_probe() first tries to get the SCP handle with scp_get(). When that\nfails, it falls back to looking up the SCP platform device with\n__get_pdev_by_id() and then reads its driver data.\n\nThe fallback lookup returns the platform device with a reference, just\nlike scp_get() does. However, the fallback path currently drops that\nreference immediately after platform_get_drvdata(). The driver later\nstill calls scp_put(mdp-\u003escp) unconditionally from the probe error path\nand from mdp_video_device_release(), which drops the SCP device\nreference again.\n\nKeep the fallback reference until the existing scp_put() call, so that\nthe fallback path follows the same ownership rules as the scp_get()\npath."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.4,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The extra put_device is in mdp_probe()/mdp_video_device_release of the MediaTek MDP3 platform driver, reached only via local driver-model bind on MT8183/MT8195 (boot, deferred probe, module load, or sysfs rebind). No network, Bluetooth/Wi-Fi, or USB path reaches this SCP refcounting.\nAC:L - On MT8183 the MDP RDMA node has no mediatek,scp phandle, so scp_get() fails and the compatible fallback is the production path. That path drops the of_find_device_by_node() ref then later scp_put() extra-puts; cmdq mailbox EPROBE_DEFER after the fallback makes this deterministic with no race.\nPR:N - mdp_probe() runs in driver-core context with no capable() or credential check. On MediaTek Chromebooks, phones, and embedded boards, MDP3 commonly deferred-probes at boot after the SCP fallback, so the extra put fires without a user account.\nUI:N - Platform probe and deferred-probe retries run unattended at boot or module bind on affected hardware. Opening /dev/video, mounting a filesystem, or plugging a device is not required.\nS:U - The extra put_device() use-after-free is of the host SCP platform_device inside the same kernel security authority. It does not cross a VM, IOMMU/DMA, or sandbox boundary.\nC:H - scp_put() extra-puts the SCP platform_device, which can run device_release and free the still-bound struct device. A use-after-free of that object enables reclaim and kernel-memory disclosure.\nI:H - The same device UAF is heap corruption of struct platform_device/mtk_scp still used by the SCP driver and other scp_get() holders, enabling heap spray, arbitrary write, and control-flow hijack.\nA:H - Freeing the SCP device while it remains registered, or later dereferencing the dangling scp pointer from MDP3/vcodec, causes a kernel oops or panic."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:54:18.396Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/dce13bd9bade3ecc1acb7579397f24743850997f"
        },
        {
          "url": "https://git.kernel.org/stable/c/252850653569fdb1a259937e02325cf32c8f0970"
        },
        {
          "url": "https://git.kernel.org/stable/c/0259ade4c4ceaf1e184a7c1aea8071ad398f9b6f"
        },
        {
          "url": "https://git.kernel.org/stable/c/55793e4665b7f15151e6f5ab51ca980e73abed5d"
        }
      ],
      "title": "media: platform: mtk-mdp3: Fix SCP device refcounting",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89885",
    "datePublished": "2026-09-16T10:31:49.746Z",
    "dateReserved": "2026-09-11T19:38:34.773Z",
    "dateUpdated": "2026-10-19T08:54:18.396Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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