# mptcp: syncookies: remember the request backup flag

CVE record · `CVE-2026-97568`

- **Identifiers:** `CVE-2026-97568`
- **State:** Confirmed
- **Severity:** No CVSS score
- **Critical:** No
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 25 Sept 2026
- **Updated:** 19 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 25 Sept 2026, 10:21 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: `1008f2bcbc8e461c1df3aebba30ac4f616ebe570 to before c97fa2c7ada82d4cac1c6c00643238dc4c462f15` (git)
  - affected: `6f01f41b6a492ddf2da7609967cfaf57e7ca48a7 to before 1668b34452009d27be3262646de748a3e48ffd51` (git)
  - affected: `09176f80995105c62939728fbad5c437d61e7ff4 to before b138e7dc719f0a3949de8bb6500b8cf1604eea06` (git)
  - affected: `8ed3e34c766e8264d5d2e0436f86c51604d6a8a7 to before 360d99258a6402cb8e49771460944f19f04d25b7` (git)
  - affected: `efd340bf3d7779a3a8ec954d8ec0fb8a10f24982 to before 61178d0b85b4b1b53e78b06e89d018d22d102f88` (git)
  - affected: `efd340bf3d7779a3a8ec954d8ec0fb8a10f24982 to before 00b2bd518911e0daab00f4749cce68c191ccebb4` (git)
  - affected: `efd340bf3d7779a3a8ec954d8ec0fb8a10f24982 to before 06d649f9cd03a9f8e768a658b20acf8d2c8022e0` (git)
  - affected: `efd340bf3d7779a3a8ec954d8ec0fb8a10f24982 to before b76c0e28b392620dfbaf92cdeedbf115820b44cb` (git)
  - affected: `73e2baa301ee3f62ff971e68877adeb37f98cc67` (git)
  - affected: `5.10.224 to before 5.10.271` (semver)
  - affected: `5.15.165 to before 5.15.222` (semver)
  - affected: `6.1.104 to before 6.1.189` (semver)
  - and 2 more
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `6.11`
  - unaffected: `before 6.11` (semver)
  - unaffected: `5.10.271 to 5.10.*, inclusive` (semver)
  - unaffected: `5.15.222 to 5.15.*, inclusive` (semver)
  - unaffected: `6.1.189 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.158 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.111 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.53 to 6.18.*, inclusive` (semver)
  - unaffected: `7.2.7 to 7.2.*, inclusive` (semver)
  - unaffected: `7.3 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

No source has published a CVSS score for this record yet.

- **CISA KEV:** Not listed.
- **EPSS:** 0.0022, the 12th percentile, on 12 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 Sept 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-97568](https://www.cve.org/CVERecord?id=CVE-2026-97568)
- [NVD: CVE-2026-97568](https://nvd.nist.gov/vuln/detail/CVE-2026-97568)

### References from the CNA

- <https://git.kernel.org/stable/c/c97fa2c7ada82d4cac1c6c00643238dc4c462f15>
- <https://git.kernel.org/stable/c/1668b34452009d27be3262646de748a3e48ffd51>
- <https://git.kernel.org/stable/c/b138e7dc719f0a3949de8bb6500b8cf1604eea06>
- <https://git.kernel.org/stable/c/360d99258a6402cb8e49771460944f19f04d25b7>
- <https://git.kernel.org/stable/c/61178d0b85b4b1b53e78b06e89d018d22d102f88>
- <https://git.kernel.org/stable/c/00b2bd518911e0daab00f4749cce68c191ccebb4>
- <https://git.kernel.org/stable/c/06d649f9cd03a9f8e768a658b20acf8d2c8022e0>
- <https://git.kernel.org/stable/c/b76c0e28b392620dfbaf92cdeedbf115820b44cb>

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-2026-97568>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-97568/>. Everything for agents: <https://agentprime.io/llms.txt>.