VulnerabilityPublished 16 Sep 2026Updated 30 Oct 2026

CVE-2026-89926: Linux kernel · KVM: s390: Fix length check __import_wp_info()

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in fec89d327d9b2b669b5bbdac209386c6317c3722 : update Linux kernel when convenient.

Data as of 30 Oct 2026, 13:03 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 fec89d327d9b2b669b5bbdac209386c6317c3722, beb9c55af609c4c7308259d7191688c75a4e3d4a, b94ab9caa5d72c78226121cccff5e33f946da900 +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.

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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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 ≥ 27291e2165b6de70c476b7b675308113edd69a60, < fec89d327d9b2b669b5bbdac209386c6317c3722	Fixed in fec89d327d9b2b669b5bbdac209386c6317c3722
LinuxLinux	Affected ≥ 27291e2165b6de70c476b7b675308113edd69a60, < beb9c55af609c4c7308259d7191688c75a4e3d4a	Fixed in beb9c55af609c4c7308259d7191688c75a4e3d4a
LinuxLinux	Affected ≥ 27291e2165b6de70c476b7b675308113edd69a60, < b94ab9caa5d72c78226121cccff5e33f946da900	Fixed in b94ab9caa5d72c78226121cccff5e33f946da900
LinuxLinux	Affected ≥ 27291e2165b6de70c476b7b675308113edd69a60, < aef540194effd768bed0bd2e6a74fe135a3d7c3a	Fixed in aef540194effd768bed0bd2e6a74fe135a3d7c3a
LinuxLinux	Affected ≥ 27291e2165b6de70c476b7b675308113edd69a60, < 71153d3262517e1c02c3a66aa5094f279b2d1454	Fixed in 71153d3262517e1c02c3a66aa5094f279b2d1454
LinuxLinux	Affected ≥ 27291e2165b6de70c476b7b675308113edd69a60, < 36d62dfb3cac66e6a97fd850a592c2ed56e35ba5	Fixed in 36d62dfb3cac66e6a97fd850a592c2ed56e35ba5

AI-suggested

A patch is available and has been applied in multiple Linux kernel commits. Users should update to a fixed kernel version containing these commits to remediate the vulnerability. Since this is a kernel-level issue, applying the official kernel update is the recommended mitigation.

Description

A vulnerability in the Linux kernel's KVM s390 module involves improper length checking in the __import_wp_info() function. The issue arises because a 64-bit length value controlled by userspace is truncated to an int for bounds checking, but the allocation uses the original 64-bit value. This discrepancy can cause allocations larger than 4GB, leading to allocation failures and kernel warnings. The flaw has been fixed in several Linux kernel commits.

Impact

Userspace can cause the kernel to attempt very large memory allocations (>4GB) due to improper length validation, resulting in allocation failures and kernel warnings. This may lead to kernel instability or denial of service conditions but does not indicate direct code execution or privilege escalation from the provided data.

Summary

The Linux kernel KVM s390 module had a vulnerability where struct kvm_hw_breakpoint::len, a 64-bit user-controlled value, was truncated to an int for bounds checking in __import_wp_info(). However, the memory allocation used the original 64-bit length, allowing userspace to trigger allocations greater than 4GB that would fail and cause kernel WARN messages. The fix ensures the validated truncated length is used for allocation, preventing this mismatch and potential kernel instability.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 30 Oct 2026, 13:03 UTC

Technical details

References

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