{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-90074",
  "modified": "2026-10-07T17:22:01Z",
  "upstream": [
    "CVE-2026-90074"
  ],
  "published": "2026-09-17T16:10:40Z",
  "summary": "net/sched: fq_pie: clamp default quantum to avoid signed overflow",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: fq_pie: clamp default quantum to avoid signed overflow\n\nfq_pie_init() sets q->quantum = psched_mtu(qdisc_dev(sch)) without\nclamping. A device with a huge MTU (e.g. dummy with max_mtu == 0\naccepting MTU 2147483634) makes psched_mtu() return 0x80000000, which\noverflows the signed flow->deficit to INT_MIN in fq_pie_qdisc_dequeue(),\ncausing an infinite loop and soft lockup. Emulate fq_pie_policy which\nis already bounded to [1, 1 << 20]; clamp the default to [256, 1 << 20].\n256 matches fq_codel's floor and is a sane minimum for a DRR quantum.\n\nConditions to recreate the bug: a device whose MTU (plus\nhard_header_len) wraps psched_mtu() into the sign bit (e.g. a dummy\ndevice with max_mtu == 0 accepting MTU 2147483634). Requires\nCAP_NET_ADMIN in a user namespace.",
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.188",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-90074"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/1f43e4dbc93b7d02761a024d5f895df823c07b72"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/f7942b2693bc24c7d609a03d06f97bee3b0bd96a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/6f1be05faecef4c0f9a008200209f66ef2e133f7"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/435da3734a8e63d3067016accc977ed1d10aaaa0"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/44dad8fe99b58a7fe2961e9eec6a5f07ace5b51f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/044fa2498bbc2900f0c48a6ef2fdd5b2bdfc3795"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/bf97fd2163ad1191ef8daa3d4df8372aee19e396"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/c86cd7ed0b0e44779a3d1683f03e4353baf4bdc9"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-09-17T16:10:40Z"
  }
}