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NVD / CVE Program· CNA Linux

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

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.21% (FIRST EPSS).
  • Fixed version: Linux Linux 321f650493d6b8169dacd4d5d6f63550dce54d6c, 4c19c302cc577bd6b466f6d8e97971777392c2fa, 4cc1ba2b31065a48fde14e9d53ad399a3ca32e35.

Low priority for now. Upgrade to Linux Linux 321f650493d6b8169dacd4d5d6f63550dce54d6c, 4c19c302cc577bd6b466f6d8e97971777392c2fa, 4cc1ba2b31065a48fde14e9d53ad399a3ca32e35 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

—No exploit Fix available
Published
Sep 17, 2026
Updated
Oct 30, 2026
EPSS
0.2% · 11th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

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Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.12affected
    • 7e279d78664aa91107ebff4b03eca367967f5908 and later · before 321f650493d6b8169dacd4d5d6f63550dce54d6caffected · git
    • 7e279d78664aa91107ebff4b03eca367967f5908 and later · before 4cc1ba2b31065a48fde14e9d53ad399a3ca32e35affected · git
    • 7e279d78664aa91107ebff4b03eca367967f5908 and later · before ca1f4a926d08035c52c735a42200e4e5ea548f32affected · git
    • 7e279d78664aa91107ebff4b03eca367967f5908 and later · before aa17842bbccaeaba7d05c166019d1c96a41bca54affected · git
    • 7e279d78664aa91107ebff4b03eca367967f5908 and later · before 4c19c302cc577bd6b466f6d8e97971777392c2faaffected · git
    • 7e279d78664aa91107ebff4b03eca367967f5908 and later · before cee0d90bceae1dee3bcc70f8d6b2ceb5b87deb42affected · git
    • before 5.12not affected · semver
    • 6.1.191 and later · up to and including 6.1.*not affected · semver
    • 6.6.160 and later · up to and including 6.6.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxfrom 0—
Debian:14linuxbefore 7.2.6-17.2.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-90095Sep 17, 2026 · fuse: Fix the condition to enable over-io-uring
    0Monitor
  • ← EarlierCVE-2026-90096Sep 17, 2026 · fuse: invalidate the correct range after O_APPEND direct write
    0Monitor
  • Later →CVE-2026-90098Sep 17, 2026 · net: sparx5: fix sleep in atomic context in MAC table access
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux321f650493d6b8169dacd4d5d6f63550dce54d6cVendor (CNA)
Linux Linux4c19c302cc577bd6b466f6d8e97971777392c2faVendor (CNA)
Linux Linux4cc1ba2b31065a48fde14e9d53ad399a3ca32e35Vendor (CNA)
Linux Linuxaa17842bbccaeaba7d05c166019d1c96a41bca54Vendor (CNA)
Linux Linuxca1f4a926d08035c52c735a42200e4e5ea548f32Vendor (CNA)
Linux Linuxcee0d90bceae1dee3bcc70f8d6b2ceb5b87deb42Vendor (CNA)
debian:linux7.2.6-1 · Debian:14Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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