CVE-2026-53183mptcp: allow subflow rcv wnd to shrink
- 7.5HighCVSS base score
- 0.49%Exploitation in 30 daysEPSS · top 57% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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.
Timeline
ID reserved
By Linux
- 16 days later
· 16 days later
Published
- 4 months later
· 4 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.49% · top 57% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
- affected f3589be0c420a3137e5902d15705ced6a36f3f43 – < bf364b0f10b27679140699821f88af7f01e2a6e3
- affected f3589be0c420a3137e5902d15705ced6a36f3f43 – < b1fd13074f22105deec45aa02283e322733e0c2d
- affected f3589be0c420a3137e5902d15705ced6a36f3f43 – < aa3861f40ac32706d9e97bfac76984613e278788
- affected f3589be0c420a3137e5902d15705ced6a36f3f43 – < 653245266913f03fcf21cbca68eed5c197a33e52
- affected f3589be0c420a3137e5902d15705ced6a36f3f43 – < c297a4e65c50a2b807d9309b22615080faffa8f3
- affected f3589be0c420a3137e5902d15705ced6a36f3f43 – < da23be77e1292cd611e736c3aa17da633d7ddce7
- affected 5.19
- unaffected < 5.19
- unaffected 6.1.176 – ≤ 6.1.*
- unaffected 6.6.143 – ≤ 6.6.*
- unaffected 6.12.94 – ≤ 6.12.*
- unaffected 6.18.36 – ≤ 6.18.*
- unaffected 7.0.13 – ≤ 7.0.*
- unaffected 7.1 – ≤ *
References
References7
- https://git.kernel.org/stable/c/bf364b0f10b27679140699821f88af7f01e2a6e3 (opens in a new tab)
- https://git.kernel.org/stable/c/b1fd13074f22105deec45aa02283e322733e0c2d (opens in a new tab)
- https://git.kernel.org/stable/c/aa3861f40ac32706d9e97bfac76984613e278788 (opens in a new tab)
- https://git.kernel.org/stable/c/653245266913f03fcf21cbca68eed5c197a33e52 (opens in a new tab)
- https://git.kernel.org/stable/c/c297a4e65c50a2b807d9309b22615080faffa8f3 (opens in a new tab)
- https://git.kernel.org/stable/c/da23be77e1292cd611e736c3aa17da633d7ddce7 (opens in a new tab)
- https://cert-portal.siemens.com/productcert/html/ssa-784472.html (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-39274 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-53183)Record last updated .