UBUNTU-CVE-2026-99091: Medium severity vulnerability

Published Oct 26, 2026
·
Updated

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: MGMT: Fix status of pending commands flushed on power off cmdcompletersp() receives a struct cmdlookup and, for a pending command that has no cmdcomplete callback, falls through to cmdstatusrsp(cmd, data). cmdstatusrsp() reads data as a u8 , so the status sent comes from the first byte of match->sk's representation, not from match->mgmtstatus. commit f53e1c9c726d ("Bluetooth: MGMT: Fix possible crash on mgmtindexremoved") changed the callers' data from &status to &match and updated the cmdcomplete branch to match->mgmtstatus, but left the fall-through passing data unchanged. In mgmtindexremoved() match->sk is NULL, so every such command is answered with status 0x00 (Success) instead of MGMTSTATUSINVALIDINDEX. In mgmtpoweroff() it is NULL too, unless a Set Powered command was pending: then settingsrsp() has stored that command's socket in match->sk, and the byte sent comes from the socket pointer. Either way the status the caller set, MGMTSTATUSNOTPOWERED (or MGMTSTATUSINVALIDINDEX when the device is being unregistered), is lost. Pass the status the callers set. This was seen on a QCA9377 laptop: bluetoothd's Start Discovery, pending when the adapter was powered off, was answered with Command Status 0x00 and no parameters, and bluetoothd 5.72 crashed on the zero-length success. BlueZ master has since added the length check on that path ("adapter: Fix crash on short start discovery reply", BlueZ a734b06059cb), but userspace should still be told Not Powered, not Success. Tested on Ubuntu 7.0.0-31 with a virtual controller (hcivhci): power off is held in HCI Write Scan Enable while a Start Discovery is submitted, and the flush answers it with status 0x00 before this change and 0x0f (Not Powered) after.

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade BlueZ to a version that resolves this vulnerability.

    Patch a734b06059cb

Event History

Oct 26, 2026
CVE Published
via OSV·03:16 PM
Data Sourced
via OSV·03:16 PM
DescriptionSeverityAffected Software

Frequently Asked Questions

1

What conditions trigger the incorrect status response?

The issue occurs when pending Bluetooth MGMT commands without a cmd_complete callback are flushed during device removal or power-off handling. It affects the mgmt_index_removed() path and the __mgmt_power_off() path.

2

What result does an affected system return to the caller?

During device unregistration, affected commands can be reported as successful (status 0x00) rather than MGMT_STATUS_INVALID_INDEX. During power-off, the intended MGMT_STATUS_NOT_POWERED can be lost and replaced by a value derived from a socket pointer, or otherwise an incorrect status.

3

Is this a crash issue?

The provided information describes incorrect command-status reporting, not a crash. The practical effect is that callers may receive success or another unintended status when a pending command is flushed.

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