Bug 2554865 (CVE-2026-98456)

Summary: CVE-2026-98456 kernel: Bluetooth: mgmt: fix race in read_unconf_index_list()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's Bluetooth subsystem. A race condition in the read_unconf_index_list() function allows a local user to cause an out-of-bounds write during asynchronous controller setup. This issue occurs when device state flags change between response buffer sizing and data population. A local attacker can exploit this vulnerability to cause memory corruption, resulting in a system crash and Denial of Service (DoS).
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-10-18 15:24:01 UTC 
In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: mgmt: fix race in read_unconf_index_list()

read_unconf_index_list() counts unconfigured controllers before allocating
its response, then checks the device flags again while filling it.

hci_dev_list_lock stabilizes list membership, but it does not serialize the
per-device flags. During asynchronous controller setup, the worker can set
HCI_UNCONFIGURED and clear HCI_SETUP between the two passes. A controller
omitted from the allocation count can then become eligible for the fill
pass, causing an out-of-bounds write to rp->index[].

Allocate space for every device on hci_dev_list. Since list membership
cannot change while hci_dev_list_lock is held, the response remains large
enough regardless of flag transitions. The reported count and response
length still include only eligible unconfigured controllers.
Comment 1 Mauro Matteo Cascella 2026-10-19 14:29:06 UTC 
Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98456.mbox