Bug 2464408 (CVE-2026-43019)

Summary: CVE-2026-43019 kernel: Bluetooth: hci_conn: fix potential UAF in set_cig_params_sync
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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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 component. Improper synchronization in the `set_cig_params_sync` function can lead to a use-after-free (UAF) vulnerability. This issue arises when `hci_conn` objects are accessed without proper locking, allowing them to be freed concurrently. An attacker could potentially exploit this to cause a denial of service or execute arbitrary code.
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Description OSIDB Bzimport 2026-05-01 15:05:09 UTC 
In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: hci_conn: fix potential UAF in set_cig_params_sync

hci_conn lookup and field access must be covered by hdev lock in
set_cig_params_sync, otherwise it's possible it is freed concurrently.

Take hdev lock to prevent hci_conn from being deleted or modified
concurrently.  Just RCU lock is not suitable here, as we also want to
avoid "tearing" in the configuration.
Comment 1 Keith Grant 2026-05-01 16:45:09 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026050157-CVE-2026-43019-0c5c@gregkh/T