FKIE_CVE-2026-97906

Vulnerability from fkie_nvd - Published: 2026-09-25 11:17 - Updated: 2026-09-25 11:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: bootconfig: Fix integer overflow in initrd size check Sashiko reported that in get_boot_config_from_initrd(), a crafted initrd with a huge bootconfig size (such as 0xFFFFFFFF) can cause the pointer arithmetic: data = ((void *)hdr) - size; to wrap around on 32-bit systems (or when pointer subtraction overflows). Because data wraps around, the subsequent bounds check: if ((unsigned long)data < initrd_start) evaluates to false, bypassing the check. The kernel then calls xbc_calc_checksum(data, size), which attempts to read 4GB of memory, hitting unmapped pages and triggering a fatal kernel page fault during early boot. Furthermore, on 64-bit systems with an initrd > 4.29 GB, an unbounded 32-bit size can similarly bypass the initrd_start check. Fix this by: 1. Ensuring the initrd is at least large enough to contain the bootconfig footer and verifying hdr is within the initrd bounds. 2. Checking that size does not exceed XBC_DATA_MAX and does not exceed the available space between initrd_start and hdr before performing pointer subtraction.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7812d6dab0698001e50e8c2f901e17da3eb6f429
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/8d4343a411eaa182d323ab5b149496416015f27d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/bff9a1579e2c9b2a59fdf3793becc9d7bf5ff1a6
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "init/main.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "8d4343a411eaa182d323ab5b149496416015f27d",
              "status": "affected",
              "version": "de462e5f10718517bacf2f84c8aa2804567ef7df",
              "versionType": "git"
            },
            {
              "lessThan": "bff9a1579e2c9b2a59fdf3793becc9d7bf5ff1a6",
              "status": "affected",
              "version": "de462e5f10718517bacf2f84c8aa2804567ef7df",
              "versionType": "git"
            },
            {
              "lessThan": "7812d6dab0698001e50e8c2f901e17da3eb6f429",
              "status": "affected",
              "version": "de462e5f10718517bacf2f84c8aa2804567ef7df",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "32394df25d8e46935b442b429d74b37885c4f092",
              "versionType": "git"
            },
            {
              "lessThan": "5.7",
              "status": "affected",
              "version": "5.6.14",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "init/main.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.7"
            },
            {
              "lessThan": "5.7",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbootconfig: Fix integer overflow in initrd size check\n\nSashiko reported that in get_boot_config_from_initrd(), a crafted initrd\nwith a huge bootconfig size (such as 0xFFFFFFFF) can cause the pointer\narithmetic:\n\n    data = ((void *)hdr) - size;\n\nto wrap around on 32-bit systems (or when pointer subtraction overflows).\nBecause data wraps around, the subsequent bounds check:\n\n    if ((unsigned long)data \u003c initrd_start)\n\nevaluates to false, bypassing the check. The kernel then calls\nxbc_calc_checksum(data, size), which attempts to read 4GB of memory,\nhitting unmapped pages and triggering a fatal kernel page fault during\nearly boot. Furthermore, on 64-bit systems with an initrd \u003e 4.29 GB, an\nunbounded 32-bit size can similarly bypass the initrd_start check.\n\nFix this by:\n1. Ensuring the initrd is at least large enough to contain the bootconfig\n   footer and verifying hdr is within the initrd bounds.\n2. Checking that size does not exceed XBC_DATA_MAX and does not exceed\n   the available space between initrd_start and hdr before performing\n   pointer subtraction."
    }
  ],
  "id": "CVE-2026-97906",
  "lastModified": "2026-09-25T11:17:17.517",
  "metrics": {},
  "published": "2026-09-25T11:17:17.517",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7812d6dab0698001e50e8c2f901e17da3eb6f429"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/8d4343a411eaa182d323ab5b149496416015f27d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/bff9a1579e2c9b2a59fdf3793becc9d7bf5ff1a6"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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