Linux kernel: critical vulnerability

Linux kernel

In the Linux kernel, the following vulnerability has been resolved: mptcp: avoid combining some incoming suboptions Some MPTCP suboptions are mutually exclusive according to the RFC8684, but also because in different places, the code doesn't expect some combinations to be present.

Fix it

Linux

On 5.15.xUpgrade to Linux 5.15.218
On 6.1.xUpgrade to Linux 6.1.191
On 6.6.xUpgrade to Linux 6.6.153
On 6.12.xUpgrade to Linux 6.12.105
On 6.18.xUpgrade to Linux 6.18.46
On 7.1.xUpgrade to Linux 7.1.10
On 7.2.xUpgrade to Linux 7.2
On 5.6.xNo fixed 5.6.x listed: move to 5.15.218 or later

First seen: 3 Nov 2026
Last update: 3 Nov 2026, 22:18 UTC
Fixed in: 7.2
7.1.10
6.18.46
6.12.105
6.6.153
6.1.191
5.15.218
Identifiers: CVE-2026-80587
CVSS: 9.8
Source: news
On the menu as: Linux kernel

Check this repository for exposure to one security incident from pwned.coffee. Report first, change nothing until I say so.

## Linux kernel: critical vulnerability
Severity: critical. Patch status: patched.
Affected: Linux kernel
Fixed in: 7.2, 7.1.10, 6.18.46, 6.12.105, 6.6.153, 6.1.191, 5.15.218
Ids: CVE-2026-80587

In the Linux kernel, the following vulnerability has been resolved: mptcp: avoid combining some incoming suboptions Some MPTCP suboptions are mutually exclusive according to the RFC8684, but also because in different places, the code doesn't expect some combinations to be present.

## Steps
1. This touches infrastructure (linux). Look in terraform, ansible, cloud-init, Dockerfiles and docs for the product and version we run. If it isn't in the repo, say so and list what a human should check on the box.
2. Fix by release line: Linux: 7.2; 7.1.x → 7.1.10; 6.18.x → 6.18.46; 6.12.x → 6.12.105; 6.6.x → 6.6.153; 6.1.x → 6.1.191; 5.15.x → 5.15.218; 5.6.x → no fixed 5.6.x listed: move to 5.15.218 or later.

## Fix by release line
| Line | State | Fix | Until then |
|---|---|---|---|
| Linux | fixed | 7.2 | — |
| Linux 7.1.x | fixed | 7.1.10 | — |
| Linux 6.18.x | fixed | 6.18.46 | — |
| Linux 6.12.x | fixed | 6.12.105 | — |
| Linux 6.6.x | fixed | 6.6.153 | — |
| Linux 6.1.x | fixed | 6.1.191 | — |
| Linux 5.15.x | fixed | 5.15.218 | — |
| Linux 5.6.x | migrate | move to 5.15.218 | restrict network access to it |

## Report
A table: file, product or package, version in use, affected yes/no, exact fix. Then anything a human has to check outside the repo.

If you have the pwned.coffee MCP server (https://pwned.coffee/mcp), call lookup_cve("CVE-2026-80587") for the latest, and check_repo with this repo's lockfiles, Dockerfiles and workflows for a full receipt.
Sources: https://git.kernel.org/stable/c/099bfcbd0c16ae9b50aba2a1bea033e63f895da7 https://nvd.nist.gov/vuln/detail/CVE-2026-80587
https://pwned.coffee/i/in-the-linux-kernel-the-following-vulnerability-has-been-cve-2026-80587

Timeline

3 Nov 2026, 22:19 UTC
Fix status: unknown → patched.
3 Nov 2026
First reported.

Receipt

Exploitation: No known exploitation
Fix by release line: Product Affected Fixed in Source
Linux before 7.2 7.2 CVE record (CNA) checked 3 Nov
Linux 7.1 to before 7.1.10 7.1.10 CVE record (CNA) checked 3 Nov
Linux 6.18 to before 6.18.46 6.18.46 CVE record (CNA) checked 3 Nov
Linux 6.12 to before 6.12.105 6.12.105 CVE record (CNA) checked 3 Nov
Linux 6.6 to before 6.6.153 6.6.153 CVE record (CNA) checked 3 Nov
Linux 6.1 to before 6.1.191 6.1.191 CVE record (CNA) checked 3 Nov
Linux 5.15 to before 5.15.218 5.15.218 CVE record (CNA) checked 3 Nov
Linux = 5.6 no fixed 5.6.x listed: move to 5.15.218 or later CVE record (CNA) checked 3 Nov
Score: CVSS 9.8 (critical). CVSS 3.1 9.8 (CNA Linux) for CVE-2026-80587
Last checked: 3 Nov 2026, 22:19 UTC

Product	Affected	Fixed in	Source
Linux	before 7.2	7.2	CVE record (CNA) checked 3 Nov
Linux	7.1 to before 7.1.10	7.1.10	CVE record (CNA) checked 3 Nov
Linux	6.18 to before 6.18.46	6.18.46	CVE record (CNA) checked 3 Nov
Linux	6.12 to before 6.12.105	6.12.105	CVE record (CNA) checked 3 Nov
Linux	6.6 to before 6.6.153	6.6.153	CVE record (CNA) checked 3 Nov
Linux	6.1 to before 6.1.191	6.1.191	CVE record (CNA) checked 3 Nov
Linux	5.15 to before 5.15.218	5.15.218	CVE record (CNA) checked 3 Nov
Linux	= 5.6	no fixed 5.6.x listed: move to 5.15.218 or later	CVE record (CNA) checked 3 Nov

Sources: KEV – CVE record ✓ Vendor ✓

Sources

Totalone very hot coffee