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VulnerabilityPublished Updated

CVE-2026-89921: Linux kernel · KVM: s390: Zero initialize data structures for inject_pfault_token

Source GCVE Database

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Authoritative record:CVE-2026-89921· Medium

Not known to be exploited · fixed in b8abc760fa18a389319d977834a30550b3ec18e8 : update Linux kernel when convenient.

Data as of 30 Oct 2026, 19:20 UTC

Severity
Medium

Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD

Thin evidence

One scorer or none
Patch
Available – fixed in b8abc760fa18a389319d977834a30550b3ec18e8, ab1a8a3c9971200938093370da4c67d4427c25f2, 7090818ba774d254eba80979c2d4da23d91de02f +5

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 16 Sep 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 383d0b050106abecb82f43101cac94fa423af5cd, < b8abc760fa18a389319d977834a30550b3ec18e8
Fixed in
  • b8abc760fa18a389319d977834a30550b3ec18e8
LinuxLinuxAffected
  • ≥ 383d0b050106abecb82f43101cac94fa423af5cd, < ab1a8a3c9971200938093370da4c67d4427c25f2
Fixed in
  • ab1a8a3c9971200938093370da4c67d4427c25f2
LinuxLinuxAffected
  • ≥ 383d0b050106abecb82f43101cac94fa423af5cd, < 7090818ba774d254eba80979c2d4da23d91de02f
Fixed in
  • 7090818ba774d254eba80979c2d4da23d91de02f
LinuxLinuxAffected
  • ≥ 383d0b050106abecb82f43101cac94fa423af5cd, < 134f235e0e8de54611a72d3cc3f63e5f31246baa
Fixed in
  • 134f235e0e8de54611a72d3cc3f63e5f31246baa
LinuxLinuxAffected
  • ≥ 383d0b050106abecb82f43101cac94fa423af5cd, < 9b046de62b8098af6e2ba820b125ec9dc5f162c8
Fixed in
  • 9b046de62b8098af6e2ba820b125ec9dc5f162c8
LinuxLinuxAffected
  • ≥ 383d0b050106abecb82f43101cac94fa423af5cd, < 5b0ae4443383fbacd905522f0c95ad6c85a3b43e
Fixed in
  • 5b0ae4443383fbacd905522f0c95ad6c85a3b43e

AI-suggested

A fix has been implemented that zero-initializes the affected data structures. Users should apply the official Linux kernel updates that include this patch once available. No additional mitigation is indicated.

Description

A vulnerability in the Linux kernel's KVM s390 subsystem involves uninitialized data structures used in the inject_pfault_token function. Specifically, certain fields of an on-stack struct are not fully initialized, potentially exposing stale stack data to host users via migration ioctls. The issue does not leak data to guests during interrupt delivery. The vulnerability has been fixed by zero-initializing the affected data structures.

References

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