Vulnerability-Lookup

GHSA-GH29-FQ9G-3P7H

Vulnerability from github – Published: 2026-05-27 15:33 – Updated: 2026-05-27 15:33

Details

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.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-45889"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-27T14:17:02Z",
    "severity": null
  },
  "details": "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": "GHSA-gh29-fq9g-3p7h",
  "modified": "2026-05-27T15:33:14Z",
  "published": "2026-05-27T15:33:14Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-45889"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/400ee4854adef1e4983812a3decf6717ea020136"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6b329393502e5857662b851a13f947209c588587"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fb7bf00b04a6b48859f52035d4e745848c2b4c79"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-45889 (GCVE-0-2026-45889)

Vulnerability from cvelistv5 – Published: 2026-05-27 12:17 – Updated: 2026-05-27 12:17

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.

Severity

No CVSS data available.

Assigner

Linux

References

3 references

URL	Tags
https://git.kernel.org/stable/c/fb7bf00b04a6b4885…
https://git.kernel.org/stable/c/400ee4854adef1e49…
https://git.kernel.org/stable/c/6b329393502e58576…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: e118cdc34dd109562b64f6a397f68cd33b041d5b , < fb7bf00b04a6b48859f52035d4e745848c2b4c79 (git) Affected: e118cdc34dd109562b64f6a397f68cd33b041d5b , < 400ee4854adef1e4983812a3decf6717ea020136 (git) Affected: e118cdc34dd109562b64f6a397f68cd33b041d5b , < 6b329393502e5857662b851a13f947209c588587 (git)
Linux	Linux	Affected: 6.18 Unaffected: 0 , < 6.18 (semver) Unaffected: 6.18.14 , ≤ 6.18.* (semver) Unaffected: 6.19.4 , ≤ 6.19.* (semver) Unaffected: 7.0 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/mptcp/protocol.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "fb7bf00b04a6b48859f52035d4e745848c2b4c79",
              "status": "affected",
              "version": "e118cdc34dd109562b64f6a397f68cd33b041d5b",
              "versionType": "git"
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            {
              "lessThan": "400ee4854adef1e4983812a3decf6717ea020136",
              "status": "affected",
              "version": "e118cdc34dd109562b64f6a397f68cd33b041d5b",
              "versionType": "git"
            },
            {
              "lessThan": "6b329393502e5857662b851a13f947209c588587",
              "status": "affected",
              "version": "e118cdc34dd109562b64f6a397f68cd33b041d5b",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
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            "net/mptcp/protocol.c"
          ],
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          "versions": [
            {
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              "version": "6.18"
            },
            {
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
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              "version": "6.18.14",
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            },
            {
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            },
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              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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          "nodes": [
            {
              "cpeMatch": [
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                  "versionStartIncluding": "6.18",
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                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-27T12:17:00.509Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/6b329393502e5857662b851a13f947209c588587"
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      ],
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    "cveId": "CVE-2026-45889",
    "datePublished": "2026-05-27T12:17:00.509Z",
    "dateReserved": "2026-05-13T15:03:33.082Z",
    "dateUpdated": "2026-05-27T12:17:00.509Z",
    "state": "PUBLISHED"
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}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-GH29-FQ9G-3P7H

CVE-2026-45889 (GCVE-0-2026-45889)

Tags

Sightings

Nomenclature