CVE-2026-31497
Received Received - Intake
Out-of-Bounds Read in Linux btusb SCO Altsetting Lookup

Publication date: 2026-04-22

Last updated on: 2026-04-28

Assigner: kernel.org

Description
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[].
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Meta Information
Published
2026-04-22
Last Modified
2026-04-28
Generated
2026-06-16
AI Q&A
2026-04-22
EPSS Evaluated
2026-06-15
NVD
CVE-2026-31497
EUVD
EUVD-2026-24870
Affected Vendors & Products
Showing 15 associated CPEs
Vendor Product Version / Range
linux linux_kernel 5.8
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel From 5.11 (inc) to 5.15.203 (exc)
linux linux_kernel From 5.16 (inc) to 6.1.168 (exc)
linux linux_kernel From 6.13 (inc) to 6.18.21 (exc)
linux linux_kernel From 6.19 (inc) to 6.19.11 (exc)
linux linux_kernel From 6.2 (inc) to 6.6.131 (exc)
linux linux_kernel From 6.7 (inc) to 6.12.80 (exc)
linux linux_kernel From 5.8.1 (inc) to 5.10.253 (exc)
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Exploitability
CWE
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CWE ID Description
CWE-UNKNOWN
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Executive Summary

This vulnerability exists in the Linux kernel's Bluetooth USB driver (btusb). The function btusb_work() uses a lookup table with three entries to map the number of active SCO (Synchronous Connection-Oriented) links to USB alternate settings when handling CVSD traffic with transparent voice settings.

The issue arises because the code indexes the lookup table using data->sco_num - 1 without first ensuring that sco_num is within the valid range of the table entries. Since the table only supports up to three SCO links, if sco_num exceeds this, the code may read beyond the bounds of the table.

The fix involves capping the lookup index to the last valid table entry, preventing out-of-bounds access and ensuring the driver selects the highest supported alternate setting without reading past the table.

Impact Analysis

This vulnerability could lead to out-of-bounds memory access in the Bluetooth USB driver when handling SCO links. Such memory access issues can potentially cause system instability, crashes, or unexpected behavior in Bluetooth functionality.

While the description does not explicitly mention exploitation scenarios, improper memory access in kernel code can sometimes be leveraged for privilege escalation or denial of service attacks.

Mitigation Strategies

The vulnerability has been resolved in the Linux kernel by clamping the SCO altsetting table indices to prevent out-of-bounds access.

To mitigate this vulnerability immediately, you should update your Linux kernel to the latest version that includes this fix.

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