# CVE-2026-89921: linux: In the Linux kernel, the following vulnerability has been resolved:  KVM: s390: Zero initialize data structures for i...

CVE-2026-89921 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-89921, released September 23, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-89921
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0022
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 16, 2026

## Description

In the Linux kernel, the following vulnerability has been resolved:  KVM: s390: Zero initialize data structures for inject_pfault_token  __kvm_inject_pfault_token() only sets .type and .u.ext.ext_params2 of the on-stack struct kvm_s390_irq but the full ext substructure is copied into the cpu local variable on inject. ext_params and pad contain stale stack values.  Interrupt delivery only uses ext_params2, so nothing leaks to the guest, but a host user can use the migration ioctls to get to the data.  Fix by zero-initializing the irq struct. Do the same for the inti data structure.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.113-1 | [DEBIAN-CVE-2026-89921](https://patchblox.com/security/data/fix/linux/debian-cve-2026-89921.md) | Sep 23, 2026 |
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-89921](https://patchblox.com/security/data/fix/linux/debian-cve-2026-89921.md) | Sep 23, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.113-1~deb12u1 | [DEBIAN-CVE-2026-89921](https://patchblox.com/security/data/fix/linux/debian-cve-2026-89921.md) | Sep 23, 2026 |

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Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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