CVE-2026-53183 (GCVE-0-2026-53183)

Vulnerability from cvelistv5 – Published: 2026-06-25 08:38 – Updated: 2026-06-28 06:39
VLAI
Title
mptcp: allow subflow rcv wnd to shrink
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.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: f3589be0c420a3137e5902d15705ced6a36f3f43 , < bf364b0f10b27679140699821f88af7f01e2a6e3 (git)
Affected: f3589be0c420a3137e5902d15705ced6a36f3f43 , < b1fd13074f22105deec45aa02283e322733e0c2d (git)
Affected: f3589be0c420a3137e5902d15705ced6a36f3f43 , < aa3861f40ac32706d9e97bfac76984613e278788 (git)
Affected: f3589be0c420a3137e5902d15705ced6a36f3f43 , < 653245266913f03fcf21cbca68eed5c197a33e52 (git)
Affected: f3589be0c420a3137e5902d15705ced6a36f3f43 , < c297a4e65c50a2b807d9309b22615080faffa8f3 (git)
Affected: f3589be0c420a3137e5902d15705ced6a36f3f43 , < da23be77e1292cd611e736c3aa17da633d7ddce7 (git)
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Linux Linux Affected: 5.19
Unaffected: 0 , < 5.19 (semver)
Unaffected: 6.1.176 , ≤ 6.1.* (semver)
Unaffected: 6.6.143 , ≤ 6.6.* (semver)
Unaffected: 6.12.94 , ≤ 6.12.* (semver)
Unaffected: 6.18.36 , ≤ 6.18.* (semver)
Unaffected: 7.0.13 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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  }
}


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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.

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.