# mptcp: allow subflow rcv wnd to shrink

CVE record · `CVE-2026-53183`

- **Identifiers:** `CVE-2026-53183`
- **State:** Confirmed
- **Severity:** CVSS 7.5 High
- **Critical:** No
- **CNA:** Linux
- **Weakness (CWE):** [CWE-400](https://cwe.mitre.org/data/definitions/400.html)
- **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md)
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 25 Jun 2026
- **Updated:** 19 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 25 Jun 2026, 08:38 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

## Affected products, as the CNA wrote them

- Vendor: Linux. Product: Linux.
  - affected: `f3589be0c420a3137e5902d15705ced6a36f3f43 to before bf364b0f10b27679140699821f88af7f01e2a6e3` (git)
  - affected: `f3589be0c420a3137e5902d15705ced6a36f3f43 to before b1fd13074f22105deec45aa02283e322733e0c2d` (git)
  - affected: `f3589be0c420a3137e5902d15705ced6a36f3f43 to before aa3861f40ac32706d9e97bfac76984613e278788` (git)
  - affected: `f3589be0c420a3137e5902d15705ced6a36f3f43 to before 653245266913f03fcf21cbca68eed5c197a33e52` (git)
  - affected: `f3589be0c420a3137e5902d15705ced6a36f3f43 to before c297a4e65c50a2b807d9309b22615080faffa8f3` (git)
  - affected: `f3589be0c420a3137e5902d15705ced6a36f3f43 to before da23be77e1292cd611e736c3aa17da633d7ddce7` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `5.19`
  - unaffected: `before 5.19` (semver)
  - unaffected: `6.1.176 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.143 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.94 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.36 to 6.18.*, inclusive` (semver)
  - unaffected: `7.0.13 to 7.0.*, inclusive` (semver)
  - unaffected: `7.1 to *, inclusive` (original_commit_for_fix)
  - Other versions: affected

## Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

## Severity and exploitation

- 7.5 High, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`, from CNA (Linux)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0049, the 42nd percentile, on 15 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

This record came from the full history of the CVE Program, published 25 Jun 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-53183](https://www.cve.org/CVERecord?id=CVE-2026-53183)
- [NVD: CVE-2026-53183](https://nvd.nist.gov/vuln/detail/CVE-2026-53183)

### References from the CNA

- <https://git.kernel.org/stable/c/bf364b0f10b27679140699821f88af7f01e2a6e3>
- <https://git.kernel.org/stable/c/b1fd13074f22105deec45aa02283e322733e0c2d>
- <https://git.kernel.org/stable/c/aa3861f40ac32706d9e97bfac76984613e278788>
- <https://git.kernel.org/stable/c/653245266913f03fcf21cbca68eed5c197a33e52>
- <https://git.kernel.org/stable/c/c297a4e65c50a2b807d9309b22615080faffa8f3>
- <https://git.kernel.org/stable/c/da23be77e1292cd611e736c3aa17da633d7ddce7>

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.

## Check whether this affects you

This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it. Compare the affected versions above with what you run.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), `get_advisory` returns this record and `search_advisories` finds related ones. Setup: <https://agentprime.io/mcp.md>
- As JSON: <https://api.agentprime.io/v1/advisories/CVE-2026-53183>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-53183/>. Everything for agents: <https://agentprime.io/llms.txt>.