VulnerabilityPublished 16 Sep 2026Updated 21 Oct 2026

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

Affects Linux kernelSource CVE Database V5

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

Data as of 26 Oct 2026, 13:07 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in b8abc760fa18a389319d977834a30550b3ec18e8, ab1a8a3c9971200938093370da4c67d4427c25f2, 134f235e0e8de54611a72d3cc3f63e5f31246baa +2

Exploitation evidence

Disclosed: evidence found.
CVE published 16 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 383d0b050106abecb82f43101cac94fa423af5cd, < b8abc760fa18a389319d977834a30550b3ec18e8	Fixed in b8abc760fa18a389319d977834a30550b3ec18e8
LinuxLinux	Affected ≥ 383d0b050106abecb82f43101cac94fa423af5cd, < ab1a8a3c9971200938093370da4c67d4427c25f2	Fixed in ab1a8a3c9971200938093370da4c67d4427c25f2
LinuxLinux	Affected ≥ 383d0b050106abecb82f43101cac94fa423af5cd, < 134f235e0e8de54611a72d3cc3f63e5f31246baa	Fixed in 134f235e0e8de54611a72d3cc3f63e5f31246baa
LinuxLinux	Affected ≥ 383d0b050106abecb82f43101cac94fa423af5cd, < 9b046de62b8098af6e2ba820b125ec9dc5f162c8	Fixed in 9b046de62b8098af6e2ba820b125ec9dc5f162c8
LinuxLinux	Affected ≥ 383d0b050106abecb82f43101cac94fa423af5cd, < 4e2c7f7cbc27418f9a290399b986c1b85ff93b90	Fixed in 4e2c7f7cbc27418f9a290399b986c1b85ff93b90
LinuxLinux	Affected =3.19	Fixed in–

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.

References

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