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

Vulnerability from cvelistv5 – Published: 2026-09-16 10:30 – Updated: 2026-10-21 12:48
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
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6639 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: c8a17756c42581ba1a567d1dd3b69e8f5619a7d8 , < 0cec951667a624fafaca2695c46042f45851caec (git)
Affected: c8a17756c42581ba1a567d1dd3b69e8f5619a7d8 , < 711fe7949d37656a5586244afee9523b9e5e37e9 (git)
Affected: c8a17756c42581ba1a567d1dd3b69e8f5619a7d8 , < ded6ad826fe0fd059333d3a3b3e1742c8e45ff41 (git)
Affected: c8a17756c42581ba1a567d1dd3b69e8f5619a7d8 , < d9daf9a6e7a6f82ef338a09386eefc6807100d3f (git)
Affected: c8a17756c42581ba1a567d1dd3b69e8f5619a7d8 , < c6f48e59ece0123f6a11527ad4d89b21c2d65b87 (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.2
Unaffected: 0 , < 6.2 (semver)
Unaffected: 6.6.160 , ≤ 6.6.* (semver)
Unaffected: 6.12.112 , ≤ 6.12.* (semver)
Unaffected: 6.18.51 , ≤ 6.18.* (semver)
Unaffected: 7.2.5 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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      "descriptions": [
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          "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."
        }
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              "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."
            }
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      "title": "drm/sysfb: ofdrm: Fix integer overflow in fb_size calculation",
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    "dateReserved": "2026-09-11T19:38:34.767Z",
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    "state": "PUBLISHED"
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      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "drm/sysfb: ofdrm: Fix integer overflow in fb_size calculation",
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      "version": "8"
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          }
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        "lastModified": "2026-10-21T13:20:28.067",
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      "source": "Red Hat CSAF VEX",
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      "title": "kernel: drm/sysfb: ofdrm: Fix integer overflow in fb_size calculation",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89806.json",
      "version": "3"
    }
  }
}



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