KVM: s390: Zero initialize data structures for inject_pfault_token (CVE-2026-89921) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-89921

KVM: s390: Zero initialize data structures for inject_pfault_token

Answer in brief

CVE-2026-89921 records a Unknown severity vulnerability in KVM: s390: Zero initialize data structures for inject_pfault_token. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 16, 2026Updated Sep 16, 2026Source checked Sep 16, 2026First seen by HOL Sep 16, 2026Material review Sep 16, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=383d0b050106abecb82f43101cac94fa423af5cd <9b046de62b8098af6e2ba820b125ec9dc5f162c8 \|\| >=383d0b050106abecb82f43101cac94fa423af5cd <134f235e0e8de54611a72d3cc3f63e5f31246baa \|\| >=383d0b050106abecb82f43101cac94fa423af5cd <4e2c7f7cbc27418f9a290399b986c1b85ff93b90	9b046de62b8098af6e2ba820b125ec9dc5f162c8, 134f235e0e8de54611a72d3cc3f63e5f31246baa, 4e2c7f7cbc27418f9a290399b986c1b85ff93b90
Linux/Linuxgeneric	3.19	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 9b046de62b8098af6e2ba820b125ec9dc5f162c8 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 16, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 16, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 16, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.