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

Summary

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

1. Oct 28, 2026, 10:36 AM UTCCVE published
2. Oct 28, 2026, 10:41 AM UTCFirst seen by cve.now
3. Oct 30, 2026, 12:43 PM UTCRecord last updated

Affected versions

• Linux Linux

  From 4.19.118 · fixed in 4.20; From 5.4.35 · fixed in 5.5; From 5.6.7 · fixed in 5.7

• Linux Linux

  5.7

• KernelLinux

  From 5.7.0 · fixed in 6.18.59; From 6.19.0 · fixed in 7.2.13

References 8