Bug 2466796 (CVE-2026-43059)

Summary: CVE-2026-43059 kernel: Bluetooth: MGMT: Fix list corruption and UAF in command complete handlers
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's Bluetooth Management (MGMT) component. This vulnerability arises from incorrect handling of pending commands within the Bluetooth subsystem's command completion processes. An attacker with local access could exploit this issue to trigger memory corruption and Use-After-Free (UAF) conditions, potentially leading to a kernel panic and a Denial of Service (DoS) for the system. Use-After-Free is a memory safety flaw where a program attempts to use memory after it has been freed, which can lead to unpredictable behavior or system crashes.
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Description OSIDB Bzimport 2026-05-05 17:03:08 UTC
In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: MGMT: Fix list corruption and UAF in command complete handlers

Commit 302a1f674c00 ("Bluetooth: MGMT: Fix possible UAFs") introduced
mgmt_pending_valid(), which not only validates the pending command but
also unlinks it from the pending list if it is valid. This change in
semantics requires updates to several completion handlers to avoid list
corruption and memory safety issues.

This patch addresses two left-over issues from the aforementioned rework:

1. In mgmt_add_adv_patterns_monitor_complete(), mgmt_pending_remove()
is replaced with mgmt_pending_free() in the success path. Since
mgmt_pending_valid() already unlinks the command at the beginning of
the function, calling mgmt_pending_remove() leads to a double list_del()
and subsequent list corruption/kernel panic.

2. In set_mesh_complete(), the use of mgmt_pending_foreach() in the error
path is removed. Since the current command is already unlinked by
mgmt_pending_valid(), this foreach loop would incorrectly target other
pending mesh commands, potentially freeing them while they are still being
processed concurrently (leading to UAFs). The redundant mgmt_cmd_status()
is also simplified to use cmd->opcode directly.