CVE Intelligence
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CVE-2026-99216 — Drivers: hv: Don't reset VMBus connection state on error/exit paths

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.

Published Oct 28, 2026 · Updated Oct 28, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • No scoring signals.

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
—
No EPSS score.
Affects
Linux
Linux
CVSS base
—
Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  3. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Linux Linux ≥ 74347a99e73ae00b8385f1209aaea193c670f901 and < f47ce27af80b87cc684d5c12b65506af498ac7e5≥ 74347a99e73ae00b8385f1209aaea193c670f901 and < 3195546a377c2d8d176d837e8baad5ce15d11195≥ 74347a99e73ae00b8385f1209aaea193c670f901 and < ec31dc39e835ccde0930daccece8c492d28282fcversion 5e059fc0f054309036d3f612bc8b0a502ca58545version 9f38f7b46de0747c1909e8c557aa21715dce20c5version caeeb3787167c884b955404a7e669fd77f267e44≥ 4.19.118 and < 4.20≥ 5.4.35 and < 5.5
and 2 more ≥ 5.6.7 and < 5.7version 5.7
Vulnerable CVE Program (cve.org) e CISA ADP

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Not enough vector or weakness data: use the affected application’s logs as a starting point.
application logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Record published
    Oct 28, 2026
  • Affected products added · linux/linux
    Oct 28, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Received
    Oct 28, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 28, 2026 · Alertas do Telegram
  • CVE published
    Oct 28, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

  • 1× References added · Oct 28, 2026 – Oct 28, 2026
  • 1× Official description updated · Oct 28, 2026 – Oct 28, 2026

References

3 on the record

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

  • CVE-2026-99215 power: supply: core: prevent unregistering a power supply while a callback runs 4h
  • CVE-2026-99214 drm/vc4: hdmi: Move packet RAM enable to PM runtime 4h
  • CVE-2026-99213 vsock: treat TCP_CLOSING as once-established 4h
  • CVE-2026-99212 net/rds: don't let the rdma_cm destroy an id RDS still owns on route failure 4h
  • CVE-2026-99211 netlink: reset skb headers before unicast and multicast filtering 4h
  • CVE-2026-99210 accel/rocket: clear rdev on device init failure 4h

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No CVSS score published by NVD, the CNA, CISA or GitHub so far.
  • No FIRST EPSS score.
  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No CWE classification.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-99216 is "Drivers: hv: Don't reset VMBus connection state on error/exit paths", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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