# mptcp: options: reset DSS fields in case of unexpected size

CVE record · `CVE-2026-80586`

- **Identifiers:** `CVE-2026-80586`
- **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:** 16 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: `648ef4b88673dadb8463bf0d4b10fbf33d55def8 to before 15e35fdad7a5576bf3f1c8d688877aeb5d1b506b` (git)
  - affected: `648ef4b88673dadb8463bf0d4b10fbf33d55def8 to before b1256090816ec46011601e084be580731df58fc7` (git)
  - affected: `648ef4b88673dadb8463bf0d4b10fbf33d55def8 to before 192878df582c51d440bf7b91a15f297f29f2b596` (git)
  - affected: `648ef4b88673dadb8463bf0d4b10fbf33d55def8 to before 26dac5c9ffb20812b475fdf253eb04fab99cff3b` (git)
  - affected: `648ef4b88673dadb8463bf0d4b10fbf33d55def8 to before 4e80eff5c1c893aca2ac1d202f0b256d2e52ecde` (git)
  - affected: `648ef4b88673dadb8463bf0d4b10fbf33d55def8 to before 1fade1b2ac5b1a4948e538fae7313bea57b5ac36` (git)
  - affected: `648ef4b88673dadb8463bf0d4b10fbf33d55def8 to before 27ed642a4e7e4b5df4b8522c72c457a67e052493` (git)
  - affected: `648ef4b88673dadb8463bf0d4b10fbf33d55def8 to before 35772b4981f38ba8059372cde8753e8e477e98ec` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `5.6`
  - unaffected: `before 5.6` (semver)
  - unaffected: `5.10.266 to 5.10.*, inclusive` (semver)
  - unaffected: `5.15.217 to 5.15.*, inclusive` (semver)
  - unaffected: `6.1.184 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:** 0.0040, the 34th 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-2026-80586](https://www.cve.org/CVERecord?id=CVE-2026-80586)
- [NVD: CVE-2026-80586](https://nvd.nist.gov/vuln/detail/CVE-2026-80586)

### References from the CNA

- <https://git.kernel.org/stable/c/15e35fdad7a5576bf3f1c8d688877aeb5d1b506b>
- <https://git.kernel.org/stable/c/b1256090816ec46011601e084be580731df58fc7>
- <https://git.kernel.org/stable/c/192878df582c51d440bf7b91a15f297f29f2b596>
- <https://git.kernel.org/stable/c/26dac5c9ffb20812b475fdf253eb04fab99cff3b>
- <https://git.kernel.org/stable/c/4e80eff5c1c893aca2ac1d202f0b256d2e52ecde>
- <https://git.kernel.org/stable/c/1fade1b2ac5b1a4948e538fae7313bea57b5ac36>
- <https://git.kernel.org/stable/c/27ed642a4e7e4b5df4b8522c72c457a67e052493>
- <https://git.kernel.org/stable/c/35772b4981f38ba8059372cde8753e8e477e98ec>

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-2026-80586>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-80586/>. Everything for agents: <https://agentprime.io/llms.txt>.