FKIE_CVE-2026-53183

Vulnerability from fkie_nvd - Published: 2026-06-25 09:16 - Updated: 2026-06-30 14:44
Severity
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: mptcp: allow subflow rcv wnd to shrink In MPTCP connection, the `window` field in the TCP header refers to the MPTCP-level rcv_nxt and it's right edge should not move backward. Such constraint is enforced at DSS option generation time. At the same time, the TCP stack ensures independently that the TCP-level rcv wnd right's edge does not move backward. That in turn causes artificial inflating of the MPTCP rcv window when the incoming data is acked at the TCP level and is OoO in the MPTCP sequence space (or lands in the backlog). As a consequence, the incoming traffic can exceed the receiver rcvbuf size even when the sender is not misbehaving. Prevent such scenario forcibly allowing the TCP subflow to shrink the TCP-level rcv wnd regardless of the current netns setting.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/653245266913f03fcf21cbca68eed5c197a33e52
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/aa3861f40ac32706d9e97bfac76984613e278788
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b1fd13074f22105deec45aa02283e322733e0c2d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/bf364b0f10b27679140699821f88af7f01e2a6e3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c297a4e65c50a2b807d9309b22615080faffa8f3
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/da23be77e1292cd611e736c3aa17da633d7ddce7
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/mptcp/options.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "bf364b0f10b27679140699821f88af7f01e2a6e3",
              "status": "affected",
              "version": "f3589be0c420a3137e5902d15705ced6a36f3f43",
              "versionType": "git"
            },
            {
              "lessThan": "b1fd13074f22105deec45aa02283e322733e0c2d",
              "status": "affected",
              "version": "f3589be0c420a3137e5902d15705ced6a36f3f43",
              "versionType": "git"
            },
            {
              "lessThan": "aa3861f40ac32706d9e97bfac76984613e278788",
              "status": "affected",
              "version": "f3589be0c420a3137e5902d15705ced6a36f3f43",
              "versionType": "git"
            },
            {
              "lessThan": "653245266913f03fcf21cbca68eed5c197a33e52",
              "status": "affected",
              "version": "f3589be0c420a3137e5902d15705ced6a36f3f43",
              "versionType": "git"
            },
            {
              "lessThan": "c297a4e65c50a2b807d9309b22615080faffa8f3",
              "status": "affected",
              "version": "f3589be0c420a3137e5902d15705ced6a36f3f43",
              "versionType": "git"
            },
            {
              "lessThan": "da23be77e1292cd611e736c3aa17da633d7ddce7",
              "status": "affected",
              "version": "f3589be0c420a3137e5902d15705ced6a36f3f43",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/mptcp/options.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.19"
            },
            {
              "lessThan": "5.19",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.176",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.143",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.94",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.36",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "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\nmptcp: allow subflow rcv wnd to shrink\n\nIn MPTCP connection, the `window` field in the TCP header refers to the\nMPTCP-level rcv_nxt and it\u0027s right edge should not move backward. Such\nconstraint is enforced at DSS option generation time.\n\nAt the same time, the TCP stack ensures independently that the TCP-level\nrcv wnd right\u0027s edge does not move backward. That in turn causes artificial\ninflating of the MPTCP rcv window when the incoming data is acked at the\nTCP level and is OoO in the MPTCP sequence space (or lands in the backlog).\n\nAs a consequence, the incoming traffic can exceed the receiver rcvbuf size\neven when the sender is not misbehaving.\n\nPrevent such scenario forcibly allowing the TCP subflow to shrink the\nTCP-level rcv wnd regardless of the current netns setting."
    }
  ],
  "id": "CVE-2026-53183",
  "lastModified": "2026-06-30T14:44:27.313",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-06-25T09:16:35.697",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/653245266913f03fcf21cbca68eed5c197a33e52"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/aa3861f40ac32706d9e97bfac76984613e278788"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b1fd13074f22105deec45aa02283e322733e0c2d"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/bf364b0f10b27679140699821f88af7f01e2a6e3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c297a4e65c50a2b807d9309b22615080faffa8f3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/da23be77e1292cd611e736c3aa17da633d7ddce7"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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