Bug 2460657 (CVE-2026-31497)

Summary: CVE-2026-31497 kernel: Bluetooth: btusb: clamp SCO altsetting table indices
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in the Linux kernel's Bluetooth USB (btusb) driver. An attacker with control over Bluetooth connections could trigger an out-of-bounds read in the `btusb_work()` function. This occurs because the function, which maps active Synchronous Connection-Oriented (SCO) links to USB alternate settings, uses an unconstrained index when accessing an internal lookup table. This vulnerability could lead to system instability or a denial of service.
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Description OSIDB Bzimport 2026-04-22 15:03:35 UTC 
In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: btusb: clamp SCO altsetting table indices

btusb_work() maps the number of active SCO links to USB alternate
settings through a three-entry lookup table when CVSD traffic uses
transparent voice settings. The lookup currently indexes alts[] with
data->sco_num - 1 without first constraining sco_num to the number of
available table entries.

While the table only defines alternate settings for up to three SCO
links, data->sco_num comes from hci_conn_num() and is used directly.
Cap the lookup to the last table entry before indexing it so the
driver keeps selecting the highest supported alternate setting without
reading past alts[].
Comment 1 Keith Grant 2026-04-22 19:15:11 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026042203-CVE-2026-31497-f54a@gregkh/T