VulnerabilityPublished 17 Sep 2026Updated 21 Oct 2026

CVE-2026-90097: Linux kernel · Drivers: hv: vmbus: Skip VMBus module cleanup for non-nested root partition

Affects Linux kernelSource CVE Database V5

Not known to be exploited · fixed in cee0d90bceae1dee3bcc70f8d6b2ceb5b87deb42 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 13:47 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 cee0d90bceae1dee3bcc70f8d6b2ceb5b87deb42, ca1f4a926d08035c52c735a42200e4e5ea548f32, aa17842bbccaeaba7d05c166019d1c96a41bca54 +2

Exploitation evidence

Disclosed: evidence found.
CVE published 17 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 ≥ 7e279d78664aa91107ebff4b03eca367967f5908, < cee0d90bceae1dee3bcc70f8d6b2ceb5b87deb42	Fixed in cee0d90bceae1dee3bcc70f8d6b2ceb5b87deb42
LinuxLinux	Affected ≥ 7e279d78664aa91107ebff4b03eca367967f5908, < ca1f4a926d08035c52c735a42200e4e5ea548f32	Fixed in ca1f4a926d08035c52c735a42200e4e5ea548f32
LinuxLinux	Affected ≥ 7e279d78664aa91107ebff4b03eca367967f5908, < aa17842bbccaeaba7d05c166019d1c96a41bca54	Fixed in aa17842bbccaeaba7d05c166019d1c96a41bca54
LinuxLinux	Affected ≥ 7e279d78664aa91107ebff4b03eca367967f5908, < 4cc1ba2b31065a48fde14e9d53ad399a3ca32e35	Fixed in 4cc1ba2b31065a48fde14e9d53ad399a3ca32e35
LinuxLinux	Affected ≥ 7e279d78664aa91107ebff4b03eca367967f5908, < 4c19c302cc577bd6b466f6d8e97971777392c2fa	Fixed in 4c19c302cc577bd6b466f6d8e97971777392c2fa
LinuxLinux	Affected =5.12	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: Drivers: hv: vmbus: Skip VMBus module cleanup for non-nested root partition The VMBus module initialization function, hv_acpi_init(), currently does nothing when running in the root partition and root is not nested in another VM. But the initialization function reports success, so the VMBus module is indeed loaded. VMBus functionality is not actually needed, but the VMBus module must be loaded so that hv_vmbus_exists() can answer correctly. Furthermore, the mshv_root dependency on the VMBus module is needed as described in the commit message for 840b740a35bf ("mshv: Add conditional VMBus dependency"). Loading the VMBus module without actually initializing it causes failures if the module should later be unloaded. The module unload code tries to clean up things that were never initialized, resulting in memory faults and a panic. Fix this by having VMBus module exit function perform the same check for non-nested root partition, and do nothing in such a case, just like hv_acpi_init(). In the long run, the code that manages the Hyper-V provided SynIC should be refactored to better coordinate the requirements of root partition scenarios and normal VM scenarios, and to hopefully remove the hv_vmbus_exists() dependnecy between mshv_root and VMBus modules. Preventing the current unload failure scenario is an expediency until such a refactoring is done.

References

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