CVE-2026-53183mptcp: allow subflow rcv wnd to shrink
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Modified
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from f3589be0c420a3137e5902d15705ced6a36f3f43 before bf364b0f10b27679140699821f88af7f01e2a6e3; from f3589be0c420a3137e5902d15705ced6a36f3f43 before b1fd13074f22105deec45aa02283e322733e0c2d; from f3589be0c420a3137e5902d15705ced6a36f3f43 before aa3861f40ac32706d9e97bfac76984613e278788; from f3589be0c420a3137e5902d15705ced6a36f3f43 before 653245266913f03fcf21cbca68eed5c197a33e52; from f3589be0c420a3137e5902d15705ced6a36f3f43 before c297a4e65c50a2b807d9309b22615080faffa8f3; from f3589be0c420a3137e5902d15705ced6a36f3f43 before da23be77e1292cd611e736c3aa17da633d7ddce7 | CNA record |
Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem siemens:simatic_s7_1500_tm_mfp_gnu_linux_subsystem (from the name) | all versions | CISA ADP |
linux linux_kernel linux:linux_kernel | from 5.19 before 6.1.176; from 6.2 before 6.6.143; from 6.7 before 6.12.94; from 6.13 before 6.18.36; from 6.19 before 7.0.13; 7.1; 7.1; 7.1; and 3 more ranges | NVD |
References
- https://git.kernel.org/stable/c/bf364b0f10b27679140699821f88af7f01e2a6e3patch
- https://git.kernel.org/stable/c/b1fd13074f22105deec45aa02283e322733e0c2dpatch
- https://git.kernel.org/stable/c/aa3861f40ac32706d9e97bfac76984613e278788patch
- https://git.kernel.org/stable/c/653245266913f03fcf21cbca68eed5c197a33e52patch
- https://git.kernel.org/stable/c/c297a4e65c50a2b807d9309b22615080faffa8f3patch
- https://git.kernel.org/stable/c/da23be77e1292cd611e736c3aa17da633d7ddce7patch
- https://cert-portal.siemens.com/productcert/html/ssa-784472.html
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.