CVE-2026-89806 (GCVE-0-2026-89806)
Vulnerability from cvelistv5
Published
2026-09-16 10:30
Modified
2026-10-21 12:48
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: drm/sysfb: ofdrm: Fix integer overflow in fb_size calculation The framebuffer size calculation `fb_size = linebytes * height` can overflow when both values are large (e.g., 46341 * 46341 > INT_MAX). Since linebytes and height are both int types, the multiplication is performed as int * int, which results in undefined behavior on overflow. Use check_mul_overflow() to detect and prevent this overflow, consistent with the approach used in simpledrm.c and corebootdrm.c.
References
Impacted products
Vendor Product Version
Linux Linux Version: c8a17756c42581ba1a567d1dd3b69e8f5619a7d8
Version: c8a17756c42581ba1a567d1dd3b69e8f5619a7d8
Version: c8a17756c42581ba1a567d1dd3b69e8f5619a7d8
Version: c8a17756c42581ba1a567d1dd3b69e8f5619a7d8
Version: c8a17756c42581ba1a567d1dd3b69e8f5619a7d8
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/sysfb/ofdrm.c"
          ],
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        },
        {
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          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/sysfb/ofdrm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.2"
            },
            {
              "lessThan": "6.2",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.160",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.112",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
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              "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": "6.6.160",
                  "versionStartIncluding": "6.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.112",
                  "versionStartIncluding": "6.2",
                  "vulnerable": true
                },
                {
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                  "vulnerable": true
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                  "versionEndExcluding": "7.2.5",
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                  "versionEndExcluding": "7.3",
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/sysfb: ofdrm: Fix integer overflow in fb_size calculation\n\nThe framebuffer size calculation `fb_size = linebytes * height` can\noverflow when both values are large (e.g., 46341 * 46341 \u003e INT_MAX).\nSince linebytes and height are both int types, the multiplication is\nperformed as int * int, which results in undefined behavior on overflow.\n\nUse check_mul_overflow() to detect and prevent this overflow, consistent\nwith the approach used in simpledrm.c and corebootdrm.c."
        }
      ],
      "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 overflow is in ofdrm_device_create() on the local platform probe path (ofdrm_probe matching Open Firmware compatible=display); it is not reached from network protocols, Bluetooth, USB, or other remote packet handlers.\nAC:L - An attacker who supplies OF width/linebytes/height (e.g. 46341x46341) deterministically overflows the int multiply fb_size=linebytes*height; there is no race, layout luck, or other condition outside attacker control.\nPR:N - ofdrm_probe runs automatically from the platform bus with no capability check; a crafted display node can be supplied without an OS account via netboot/PXE, QEMU/hypervisor Open Firmware, or firmware, so no privileges on the running system are required.\nUI:N - Once a malicious display node is present, framebuffer size is computed during unattended driver probe; no victim mount, file open, or other interactive action is required.\nS:U - The overflow and resulting framebuffer mapping errors affect kernel and MMIO state on the same host; this is a standard in-kernel driver defect, not a VM escape, IOMMU bypass, or other cross-authority impact.\nC:H - A wrapped fb_size ioremaps a too-small aperture while scanout still uses the attacker-chosen pitch and height, enabling out-of-bounds reads of adjacent ioremap/vmalloc memory; memory-corruption OOB access is High confidentiality.\nI:H - The undersized mapping causes out-of-bounds writes through drm_sysfb blit/disable paths and DRM/fbdev clients past the mapped firmware framebuffer, which is an OOB write scored as High integrity impact.\nA:H - Accesses past the ioremap\u0027d region cause kernel page-fault oops or panic during probe-time DRM client setup or later modeset/blit, fully denying availability on affected Open Firmware display systems."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-21T12:48:48.055Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/0cec951667a624fafaca2695c46042f45851caec"
        },
        {
          "url": "https://git.kernel.org/stable/c/711fe7949d37656a5586244afee9523b9e5e37e9"
        },
        {
          "url": "https://git.kernel.org/stable/c/ded6ad826fe0fd059333d3a3b3e1742c8e45ff41"
        },
        {
          "url": "https://git.kernel.org/stable/c/d9daf9a6e7a6f82ef338a09386eefc6807100d3f"
        },
        {
          "url": "https://git.kernel.org/stable/c/c6f48e59ece0123f6a11527ad4d89b21c2d65b87"
        }
      ],
      "title": "drm/sysfb: ofdrm: Fix integer overflow in fb_size calculation",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89806",
    "datePublished": "2026-09-16T10:30:39.548Z",
    "dateReserved": "2026-09-11T19:38:34.767Z",
    "dateUpdated": "2026-10-21T12:48:48.055Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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