# KVM: s390: Zero initialize data structures for inject_pfault_token

CVE record · `CVE-2026-89921`

- **Identifiers:** `CVE-2026-89921`
- **State:** Confirmed
- **Severity:** No CVSS score
- **Critical:** No
- **CNA:** Linux
- **Technologies:** [Linux kernel](https://agentprime.io/advisories/technology/linux-kernel.md)
- **Published:** 16 Sept 2026
- **Updated:** 30 Oct 2026
- **Reviewed by a person:** No

Published by the CVE Program (CNA: Linux) at 16 Sept 2026, 10:32 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: `383d0b050106abecb82f43101cac94fa423af5cd to before 3da26db3323cbccf509005fdbc4ebae842d323cd` (git)
  - affected: `383d0b050106abecb82f43101cac94fa423af5cd to before 5b0ae4443383fbacd905522f0c95ad6c85a3b43e` (git)
  - affected: `383d0b050106abecb82f43101cac94fa423af5cd to before 7090818ba774d254eba80979c2d4da23d91de02f` (git)
  - affected: `383d0b050106abecb82f43101cac94fa423af5cd to before ab1a8a3c9971200938093370da4c67d4427c25f2` (git)
  - affected: `383d0b050106abecb82f43101cac94fa423af5cd to before b8abc760fa18a389319d977834a30550b3ec18e8` (git)
  - affected: `383d0b050106abecb82f43101cac94fa423af5cd to before 9b046de62b8098af6e2ba820b125ec9dc5f162c8` (git)
  - affected: `383d0b050106abecb82f43101cac94fa423af5cd to before 134f235e0e8de54611a72d3cc3f63e5f31246baa` (git)
  - affected: `383d0b050106abecb82f43101cac94fa423af5cd to before 4e2c7f7cbc27418f9a290399b986c1b85ff93b90` (git)
  - Other versions: unaffected
- Vendor: Linux. Product: Linux.
  - affected: `3.19`
  - unaffected: `before 3.19` (semver)
  - unaffected: `5.10.273 to 5.10.*, inclusive` (semver)
  - unaffected: `5.15.224 to 5.15.*, inclusive` (semver)
  - unaffected: `6.1.191 to 6.1.*, inclusive` (semver)
  - unaffected: `6.6.160 to 6.6.*, inclusive` (semver)
  - unaffected: `6.12.112 to 6.12.*, inclusive` (semver)
  - unaffected: `6.18.52 to 6.18.*, inclusive` (semver)
  - unaffected: `7.2.5 to 7.2.*, inclusive` (semver)
  - unaffected: `7.3 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.

> This Linux kernel KVM issue affects the s390 pfault token injection path in multiple stable branches, with the vulnerable range starting at commit 383d0b050106 and fixed in several stable releases. An attacker with access to the host's migration ioctls can read stale stack values left in kernel data structures, though the source states that nothing leaks to the guest. Upgrade to a fixed Linux kernel release for your branch, or to 3.19 or later where the fix is included; the source lists fixed versions 5.10.273, 5.15.224, 6.1.191 and 6.6.160 and their later point releases.

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

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

- **CISA KEV:** Not listed.
- **EPSS:** 0.0022, the 12th 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 16 Sept 2026. New records show when each source confirmed them.

## Sources

- [CVE List: CVE-2026-89921](https://www.cve.org/CVERecord?id=CVE-2026-89921)
- [NVD: CVE-2026-89921](https://nvd.nist.gov/vuln/detail/CVE-2026-89921)

### References from the CNA

- <https://git.kernel.org/stable/c/3da26db3323cbccf509005fdbc4ebae842d323cd>
- <https://git.kernel.org/stable/c/5b0ae4443383fbacd905522f0c95ad6c85a3b43e>
- <https://git.kernel.org/stable/c/7090818ba774d254eba80979c2d4da23d91de02f>
- <https://git.kernel.org/stable/c/ab1a8a3c9971200938093370da4c67d4427c25f2>
- <https://git.kernel.org/stable/c/b8abc760fa18a389319d977834a30550b3ec18e8>
- <https://git.kernel.org/stable/c/9b046de62b8098af6e2ba820b125ec9dc5f162c8>
- <https://git.kernel.org/stable/c/134f235e0e8de54611a72d3cc3f63e5f31246baa>
- <https://git.kernel.org/stable/c/4e2c7f7cbc27418f9a290399b986c1b85ff93b90>

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-2026-89921>
- Everything that needs attention now: <https://agentprime.io/advisories/critical.md>

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The web page: <https://agentprime.io/advisories/CVE-2026-89921/>. Everything for agents: <https://agentprime.io/llms.txt>.