# s390/vfio_ccw: Ensure first IDAW remains constant

CVE record · `CVE-2026-80551`

- **Identifiers:** `CVE-2026-80551`
- **State:** Confirmed
- **Severity:** CVSS 9.3 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 9.3: 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: `01aa26c672c0eb771de4aaa2a8ccf6055778887b to before 5b7c23440343e336259cd45017cc901a744c41b0` (git)
  - affected: `01aa26c672c0eb771de4aaa2a8ccf6055778887b to before 460b977a4e71cc319fdadf91c193ec3beaa57263` (git)
  - affected: `01aa26c672c0eb771de4aaa2a8ccf6055778887b to before 0d46c2565f173bcddcdcaf44a4f69789a20535e2` (git)
  - affected: `01aa26c672c0eb771de4aaa2a8ccf6055778887b to before 08ef2a82115690d6e229615872ac1731af732497` (git)
  - affected: `01aa26c672c0eb771de4aaa2a8ccf6055778887b to before fc59e9482117ebdccd6dc7fa8082f8b980fd021e` (git)
  - affected: `01aa26c672c0eb771de4aaa2a8ccf6055778887b to before 565bef268d75bf7df665bce6923a88cd0eb74592` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `5.3`
  - unaffected: `before 5.3` (semver)
  - unaffected: `6.1.191 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.154 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

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> The Linux kernel s390 vfio_ccw driver is affected from version 5.3 until the fix is applied. The source gives few details and does not say what an attacker needs or what they could do. Upgrade to Linux kernel 6.1.191, 6.6.154, 6.12.105, 6.18.46, or a later release in those series.

Written 12 Nov 2026.

## 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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0014, the 3rd 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-2026-80551](https://www.cve.org/CVERecord?id=CVE-2026-80551)
- [NVD: CVE-2026-80551](https://nvd.nist.gov/vuln/detail/CVE-2026-80551)

### References from the CNA

- <https://git.kernel.org/stable/c/5b7c23440343e336259cd45017cc901a744c41b0>
- <https://git.kernel.org/stable/c/460b977a4e71cc319fdadf91c193ec3beaa57263>
- <https://git.kernel.org/stable/c/0d46c2565f173bcddcdcaf44a4f69789a20535e2>
- <https://git.kernel.org/stable/c/08ef2a82115690d6e229615872ac1731af732497>
- <https://git.kernel.org/stable/c/fc59e9482117ebdccd6dc7fa8082f8b980fd021e>
- <https://git.kernel.org/stable/c/565bef268d75bf7df665bce6923a88cd0eb74592>

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-2026-80551>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-80551/>. Everything for agents: <https://agentprime.io/llms.txt>.