FKIE_CVE-2026-45889

Vulnerability from fkie_nvd - Published: 2026-05-27 14:17 - Updated: 2026-05-27 14:48
Severity
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/400ee4854adef1e4983812a3decf6717ea020136
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6b329393502e5857662b851a13f947209c588587
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/fb7bf00b04a6b48859f52035d4e745848c2b4c79
Impacted products
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: do not account for OoO in mptcp_rcvbuf_grow()\n\nMPTCP-level OoOs are physiological when multiple subflows are active\nconcurrently and will not cause retransmissions nor are caused by\ndrops.\n\nAccounting for them in mptcp_rcvbuf_grow() causes the rcvbuf slowly\ndrifting towards tcp_rmem[2].\n\nRemove such accounting. Note that subflows will still account for TCP-level\nOoO when the MPTCP-level rcvbuf is propagated.\n\nThis also closes a subtle and very unlikely race condition with rcvspace\ninit; active sockets with user-space holding the msk-level socket lock,\ncould complete such initialization in the receive callback, after that the\nfirst OoO data reaches the rcvbuf and potentially triggering a divide by\nzero Oops."
    }
  ],
  "id": "CVE-2026-45889",
  "lastModified": "2026-05-27T14:48:31.480",
  "metrics": {},
  "published": "2026-05-27T14:17:02.927",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/400ee4854adef1e4983812a3decf6717ea020136"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6b329393502e5857662b851a13f947209c588587"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/fb7bf00b04a6b48859f52035d4e745848c2b4c79"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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