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No exploitation reported

CVE-2026-99216

Drivers: hv: Don't reset VMBus connection state on error/exit paths

No exploitation reported by the sources we read.

  • Published2026-10-28

Am I affected?

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Description

In the Linux kernel, the following vulnerability has been resolved: Drivers: hv: Don't reset VMBus connection state on error/exit paths In two places, current code forces vmbus_connection.conn_state to DISCONNECTED prior to calling vmbus_disconnect(). But vmbus_disconnect() calls vmbus_initiate_unload(), which unloads the VMBus connection only if the conn_state is CONNECTED. Consequently, the connection remains and the Hyper-V host might continue to send messages or post VMBus interrupts. The problem was introduced in commit 74347a99e73ae ("x86/Hyper-V: Unload vmbus channel in hv panic callback"), in that vmbus_initiate_unload() started checking the current connection state before doing the unload. This commit removed some occurrences where conn_state was forced to DISCONNECTED, but these two remained, apparently due to an oversight at the time. Fix this by not forcing conn_state to DISCONNECTED during VMBus exit, or if a failure occurs when establishing the connection in the first place. Whatever value conn_state has at the time is then read by vmbus_initiate_unload() to determine if there is a connection to be unloaded.

Timeline

dates in UTC
  1. 2026-10-2811:17CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-31 15:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-99216?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-99216?format=csv
  • TAXII collection of exploited CVEs
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Versions per branch

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

  • CVE-2026-99216 Red Hat Product Security278 known affected

    kernel: Drivers: hv: Don't reset VMBus connection state on error/exit paths

    kernel as a component of Red Hat Enterprise Linux 10 · kernel-64k as a component of Red Hat Enterprise Linux 10 · kernel-64k-core as a component of Red Hat Enterprise Linux 10 · +275 more

Full record on NVD

Fix

  1. No fix available, says the vendor Red Hat Product Security CVE-2026-99216 · 264 productsFix deferred
  2. No fix planned, says the vendor Red Hat Product Security CVE-2026-99216 · 14 productsOut of support scope

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • NVDCVE recordread 2026-10-31
  • CNACVSS 3.18.4read 2026-10-31
  • FIRST EPSSEPSS score0.2 %2026-10-30

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2026-10-28
Last Modified
2026-10-31
NVD status
Received

Frequently asked questions

What is CVE-2026-99216?

In the Linux kernel, the following vulnerability has been resolved: Drivers: hv: Don't reset VMBus connection state on error/exit paths In two places, current code forces vmbus_connection.conn_state to DISCONNECTED prior to calling vmbus_disconnect(). But vmbus_disconnect() calls vmbus_initiate_unload(), which unloads the VMBus connection only if the conn_state is CONNECTED. Consequently, the connection remains and the Hyper-V host might continue to send messages or post VMBus interrupts. The problem was introduced in commit 74347a99e73ae ("x86/Hyper-V: Unload vmbus channel in hv panic callback"), in that vmbus_initiate_unload() started checking the current connection state before doing the unload. This commit removed some occurrences where conn_state was forced to DISCONNECTED, but these two remained, apparently due to an oversight at the time. Fix this by not forcing conn_state to DISCONNECTED during VMBus exit, or if a failure occurs when establishing the connection in the first place. Whatever value conn_state has at the time is then read by vmbus_initiate_unload() to determine if there is a connection to be unloaded.

Is CVE-2026-99216 actively exploited?

Active exploitation of CVE-2026-99216 has not been confirmed. Its EPSS score was 0.2% on 2026-10-30, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-99216?

CVE-2026-99216 has a CVSS v3 base score of 8.4 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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