CVE-2026-89806 (GCVE-0-2026-89806)

Vulnerability from cvelistv5 – Published: 2026-09-16 10:30 – Updated: 2026-09-16 14:38
VLAI
Title
drm/sysfb: ofdrm: Fix integer overflow in fb_size calculation
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.
Severity
8.4 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: c8a17756c42581ba1a567d1dd3b69e8f5619a7d8 , < ded6ad826fe0fd059333d3a3b3e1742c8e45ff41 (git)
Affected: c8a17756c42581ba1a567d1dd3b69e8f5619a7d8 , < d9daf9a6e7a6f82ef338a09386eefc6807100d3f (git)
Affected: c8a17756c42581ba1a567d1dd3b69e8f5619a7d8 , < c6f48e59ece0123f6a11527ad4d89b21c2d65b87 (git)
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Linux Linux Affected: 6.2
Unaffected: 0 , < 6.2 (semver)
Unaffected: 6.18.51 , ≤ 6.18.* (semver)
Unaffected: 7.2.5 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc2 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/gpu/drm/sysfb/ofdrm.c"
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          "vendor": "Linux",
          "versions": [
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              "negate": false,
              "operator": "OR"
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      "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": [
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          "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": "2026-09-16T14:38:52.546Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "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",
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        "engine": "bippy-1.2.0"
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89806",
    "datePublished": "2026-09-16T10:30:39.548Z",
    "dateReserved": "2026-09-11T19:38:34.767Z",
    "dateUpdated": "2026-09-16T14:38:52.546Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-09-25",
      "epss": "0.00194",
      "percentile": "0.08035"
    },
    "microsoft_vex": {
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      "id": "msrc_CVE-2026-89806",
      "initial_release_date": "2026-09-17T01:07:25.000Z",
      "product_status:known_affected": "3",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "drm/sysfb: ofdrm: Fix integer overflow in fb_size calculation",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-89806.json",
      "version": "4"
    },
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                ],
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                    "version": "7.2.5",
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                    "versionType": "original_commit_for_fix"
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        "cveTags": [],
        "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."
          }
        ],
        "id": "CVE-2026-89806",
        "lastModified": "2026-09-16T15:18:10.350",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 8.4,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
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              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-09-16T11:16:45.703",
        "references": [
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • 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.
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  • 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.



Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.