mptcp: do not account for OoO in mptcp_rcvbuf_grow()

{
  "id": "ad9b49919dd9f7a3b70470de8e928c05e3f6de2499ee40f9961e7d8aa6e0f850",
  "url": "https://osv.dev/vulnerability/CVE-2026-45889",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "mptcp: do not account for OoO in mptcp_rcvbuf_grow()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: mptcp: do not account for OoO in mptcp_rcvbuf_grow() MPTCP-level OoOs are physiological when multiple subflows are active concurrently and will not cause retransmissions nor are caused by drops. Accounting for them in mptcp_rcvbuf_grow() causes the rcvbuf slowly drifting towards tcp_rmem[2]. Remove such accounting. Note that subflows will still account for TCP-level OoO when the MPTCP-level rcvbuf is propagated. This also closes a subtle and very unlikely race condition with rcvspace init; active sockets with user-space holding the msk-level socket lock, could complete such initialization in the receive callback, after that the first OoO data reaches the rcvbuf and potentially triggering a divide by zero Oops.",
    "evidence": "osv:CVE-2026-45889",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.18.14",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.19.4",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-45889",
      "aliases": [
        "CVE-2026-45889"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "e118cdc34dd109562b64f6a397f68cd33b041d5b"
                },
                {
                  "fixed": "fb7bf00b04a6b48859f52035d4e745848c2b4c79"
                },
                {
                  "fixed": "400ee4854adef1e4983812a3decf6717ea020136"
                },
                {
                  "fixed": "6b329393502e5857662b851a13f947209c588587"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-45889.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.18.0"
                },
                {
                  "fixed": "6.18.14"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "6.19.4"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-45889.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:43.963509883Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/400ee4854adef1e4983812a3decf6717ea020136",
        "https://git.kernel.org/stable/c/6b329393502e5857662b851a13f947209c588587",
        "https://git.kernel.org/stable/c/fb7bf00b04a6b48859f52035d4e745848c2b4c79",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45889.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-45889",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45889.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-45889",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 511651,
  "published_at": "2026-05-27T12:17:00.509+00:00"
}