CVE-2026-89921: Linux kernel · KVM: s390: Zero initialize data structures for inject_pfault_token
Source GCVE Database
Not known to be exploited · fixed in b8abc760fa18a389319d977834a30550b3ec18e8 : update Linux kernel when convenient.
Data as of 30 Oct 2026, 19:20 UTC
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
Disclosed: evidence found.
CVE published 16 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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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
- nvd.nist.gov/vuln/detail/CVE-2026-89921 (opens in a new tab)
- git.kernel.org/stable/c/134f235e0e8de54611a72d3cc3f63e5f31246baa (opens in a new tab)
- git.kernel.org/stable/c/3da26db3323cbccf509005fdbc4ebae842d323cd (opens in a new tab)
- git.kernel.org/stable/c/4e2c7f7cbc27418f9a290399b986c1b85ff93b90 (opens in a new tab)
- git.kernel.org/stable/c/5b0ae4443383fbacd905522f0c95ad6c85a3b43e (opens in a new tab)
- git.kernel.org/stable/c/7090818ba774d254eba80979c2d4da23d91de02f (opens in a new tab)
- git.kernel.org/stable/c/9b046de62b8098af6e2ba820b125ec9dc5f162c8 (opens in a new tab)
- git.kernel.org/stable/c/ab1a8a3c9971200938093370da4c67d4427c25f2 (opens in a new tab)
- git.kernel.org/stable/c/b8abc760fa18a389319d977834a30550b3ec18e8 (opens in a new tab)