CVE-2026-99216

LOWCVSS 8.4 · HIGH

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Track advisory updates for patch or workaround availability

Recommended action window: Monitor and triage in normal cycle

NVD 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.

0.0/ 10 priority

Sources & remediation

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

NONE

Momentum

STABLE

Threat summary

  • 2 mentions across 2 observed days
  • Momentum state: stable

What's happening

  • Peaked 1d ago at 1 mentions (2026-10-31); latest day: 1
  • 2 total mentions across 2 days

Deep dive

Activity timeline2 mentions / 2d
00111Mentions · 2026-10-31: 1Mentions · 2026-11-01: 110-3111-01
Referenced assets3 URLs
Full discourse2 posts
  • cve.now@cvedotnow

    🔴 Linux kernel: unwanted host messages accepted in VMBus driver (CVE-2026-99216) A compromised host can keep sending messages and interrupts to the guest after VMBus should have disconnected. Disclosed Oct 28 Patch → 4.20, 5.5 and more https://cve.now/CVE-2026-99216?utm_source=x&utm_medium=social&utm_campaign=cvedotnow&utm_content=critical

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  • m.shiono@shioccii

    ⑤ CVE-2026-99216 Linuxカーネル Hyper-V VMBusドライバ CVSS 3.1: 8.4 High(https://kernel.org CNA) 切断後もホストからのメッセージ・割り込みを受け付ける 対応: 5.10.273 / 5.15.224 / 6.1.191 / 6.6.161 / 6.12.115 / 6.18.59 / 7.2.13 以降へ https://nvd.nist.gov/vuln/detail/CVE-2026-99216

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