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net/sched: fq_pie: clamp default quantum to avoid signed overflow

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: net/sched: fq_pie: clamp default quantum to avoid signed overflow fq_pie_init() sets q->quantum = psched_mtu(qdisc_dev(sch)) without clamping. A device with a huge MTU (e.g. dummy with max_mtu == 0 accepting MTU 2147483634) makes psched_mtu() return 0x80000000, which overflows the signed flow->deficit to INT_MIN in fq_pie_qdisc_dequeue(), causing an infinite loop and soft lockup. Emulate fq_pie_policy which is already bounded to [1, 1 << 20]; clamp the default to [256, 1 << 20]. 256 matches fq_codel's floor and is a sane minimum for a DRR quantum. Conditions to recreate the bug: a device whose MTU (plus hard_header_len) wraps psched_mtu() into the sign bit (e.g. a dummy device with max_mtu == 0 accepting MTU 2147483634). Requires CAP_NET_ADMIN in a user namespace.

Announced Source revision 1
Original source ↗

CVE-2026-90074

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-90074

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "ec97ecf1ebe485a17cd8395a5f35e6b80b57665a",
        "lessThan": "1f43e4dbc93b7d02761a024d5f895df823c07b72",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "ec97ecf1ebe485a17cd8395a5f35e6b80b57665a",
        "lessThan": "f7942b2693bc24c7d609a03d06f97bee3b0bd96a",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "ec97ecf1ebe485a17cd8395a5f35e6b80b57665a",
        "lessThan": "6f1be05faecef4c0f9a008200209f66ef2e133f7",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "ec97ecf1ebe485a17cd8395a5f35e6b80b57665a",
        "lessThan": "435da3734a8e63d3067016accc977ed1d10aaaa0",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "ec97ecf1ebe485a17cd8395a5f35e6b80b57665a",
        "lessThan": "44dad8fe99b58a7fe2961e9eec6a5f07ace5b51f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "ec97ecf1ebe485a17cd8395a5f35e6b80b57665a",
        "lessThan": "044fa2498bbc2900f0c48a6ef2fdd5b2bdfc3795",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "ec97ecf1ebe485a17cd8395a5f35e6b80b57665a",
        "lessThan": "bf97fd2163ad1191ef8daa3d4df8372aee19e396",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "ec97ecf1ebe485a17cd8395a5f35e6b80b57665a",
        "lessThan": "c86cd7ed0b0e44779a3d1683f03e4353baf4bdc9",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/sched/sch_fq_pie.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.6"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.6",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.270",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.221",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.188",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.157",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.110",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.52",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.6",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/sched/sch_fq_pie.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-90074

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#36490 · Revision 1
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