# mptcp: avoid combining some incoming suboptions

CVE record · `CVE-2026-80587`

- **Identifiers:** `CVE-2026-80587`
- **State:** Confirmed
- **Severity:** CVSS 9.8 Critical
- **Critical:** Yes: CVSS 9+
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 26 Aug 2026
- **Updated:** 30 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 26 Aug 2026, 14:37 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.

## Critical

Critical, because:

- CVSS score 9.8: 9.0 or more.

How we decide what’s critical: <https://agentprime.io/advisories/critical.md>

## Affected products, as the CNA wrote them

- Vendor: Linux. Product: Linux.
  - affected: `eda7acddf8080bb2d022a8d4b8b2345eb80c63ec to before 0e2210af439755a2af352eea4178261dcf61742e` (git)
  - affected: `eda7acddf8080bb2d022a8d4b8b2345eb80c63ec to before d1bce616636c1c42649966677973490a510055c4` (git)
  - affected: `eda7acddf8080bb2d022a8d4b8b2345eb80c63ec to before dc1d8d3eb345c616fbe922a010fa391c72c54d52` (git)
  - affected: `eda7acddf8080bb2d022a8d4b8b2345eb80c63ec to before 099bfcbd0c16ae9b50aba2a1bea033e63f895da7` (git)
  - affected: `eda7acddf8080bb2d022a8d4b8b2345eb80c63ec to before a04dcc784959e4702048785d87e0d029bd2fbdcb` (git)
  - affected: `eda7acddf8080bb2d022a8d4b8b2345eb80c63ec to before 6bab907292155513af397a12ccb488acbfc30d79` (git)
  - affected: `eda7acddf8080bb2d022a8d4b8b2345eb80c63ec to before b6ee361524641f57b2e2363f7737f20e17f67827` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `5.6`
  - unaffected: `before 5.6` (semver)
  - unaffected: `5.15.218 to 5.15.*, inclusive` (semver)
  - unaffected: `6.1.191 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.153 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.105 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.46 to 6.18.*, inclusive` (semver)
  - unaffected: `7.1.10 to 7.1.*, inclusive` (semver)
  - unaffected: `7.2 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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0052, the 44th 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 26 Aug 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-80587](https://www.cve.org/CVERecord?id=CVE-2026-80587)
- [NVD: CVE-2026-80587](https://nvd.nist.gov/vuln/detail/CVE-2026-80587)

### References from the CNA

- <https://git.kernel.org/stable/c/0e2210af439755a2af352eea4178261dcf61742e>
- <https://git.kernel.org/stable/c/d1bce616636c1c42649966677973490a510055c4>
- <https://git.kernel.org/stable/c/dc1d8d3eb345c616fbe922a010fa391c72c54d52>
- <https://git.kernel.org/stable/c/099bfcbd0c16ae9b50aba2a1bea033e63f895da7>
- <https://git.kernel.org/stable/c/a04dcc784959e4702048785d87e0d029bd2fbdcb>
- <https://git.kernel.org/stable/c/6bab907292155513af397a12ccb488acbfc30d79>
- <https://git.kernel.org/stable/c/b6ee361524641f57b2e2363f7737f20e17f67827>

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-2026-80587>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-80587/>. Everything for agents: <https://agentprime.io/llms.txt>.