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tcp: fix TFO max_qlen accounting across reuseport migration

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: tcp: fix TFO max_qlen accounting across reuseport migration A listener's TCP_FASTOPEN max_qlen stops being accurate and lets through far more pending Fast Open requests than it was configured for. This only shows up with SO_REUSEPORT listener migration, where closing a listener hands its still-pending TFO children over to a surviving one. fastopenq.qlen is charged in tcp_fastopen_create_child() when the child is created and uncharged in reqsk_fastopen_remove() when the handshake completes. The uncharge follows rsk_listener of the request the child points at, and inet_reqsk_clone() has repointed the child at a new request owned by the new listener, so the ++ and the -- land on two different sockets. The new listener's qlen drifts negative and its limit no longer binds. Charge the new listener during migration, like reqsk_queue_migrated() already does for queue->young and queue->qlen.

Announced Source revision 1
Original source ↗

CVE-2026-74696

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-2026-74696

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": "54b92e84193749c9968aff2dd46e3b0f42643e18",
        "lessThan": "e98f0d80b9cccb5f828425d2004f9686e7d1ae24",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "54b92e84193749c9968aff2dd46e3b0f42643e18",
        "lessThan": "b6247e0f96bd825ffb2005257f6177b5e642dee6",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "54b92e84193749c9968aff2dd46e3b0f42643e18",
        "lessThan": "585fc5247d14939a561056aa2addd9b7c2b1f670",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "54b92e84193749c9968aff2dd46e3b0f42643e18",
        "lessThan": "6e10ee56524a26b250229ad348637825646ddb88",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "54b92e84193749c9968aff2dd46e3b0f42643e18",
        "lessThan": "a66e869cf0c90c1e47ae75f72b6482acbfc808ff",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "54b92e84193749c9968aff2dd46e3b0f42643e18",
        "lessThan": "d974618b2097453778389d385e3741629c40e0a3",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "54b92e84193749c9968aff2dd46e3b0f42643e18",
        "lessThan": "a0ab2ba83e35159d81cec830a92e885ecf8139be",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/ipv4/inet_connection_sock.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.14"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.14",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.15.216",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.183",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.152",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.104",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.45",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.9",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/ipv4/inet_connection_sock.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-74696

Source reference: /cveMetadata/cveId

Publisher severity

high

Source reference: /containers/cna/metrics

Event
#34274 · Revision 1
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Publisher date
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