# CVE-2026-64557: Bluetooth: L2CAP: Fix use-after-free in l2cap_sock_new_connection_cb()

> A use-after-free in the Linux kernel Bluetooth L2CAP module allows attackers to execute arbitrary code or escalate privileges via crafted connections.

- **Severity:** High 8.8 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 29 Jul 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-94143, BELL-CVE-2026-64557, DEBIAN-CVE-2026-64557, GHSA-57gr-rx4p-h42m, ROOT-OS-DEBIAN-12-CVE-2026-64557, UBUNTU-CVE-2026-64557

## What is CVE-2026-64557?

CVE-2026-64557 is a high-severity use after free vulnerability in Linux, published on 29 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: L2CAP: Fix use-after-free in l2cap_sock_new_connection_cb()

l2cap_sock_new_connection_cb() returned l2cap_pi(sk)->chan after
release_sock(parent). Once the parent lock is dropped the newly
enqueued child socket sk is reachable via the accept queue, so another
task can accept and free it before the callback dereferences sk,
resulting in a use-after-free.

Rework the ->new_connection() op so the core, rather than the callback,
owns the child channel's lifetime. The op now receives a pre-allocated
new_chan and returns an errno instead of allocating and returning a
channel. l2cap_new_connection() allocates the child channel and links
it into the conn list via __l2cap_chan_add() before invoking the
callback, so the conn-list reference keeps the channel alive once
release_sock(parent) exposes the socket to other tasks.

Channel configuration that was duplicated in l2cap_sock_init() and the
various new_connection callbacks is consolidated into
l2cap_chan_set_defaults(), which now inherits from the parent channel
when one is supplied.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-64557?


## How do I fix CVE-2026-64557?

Apply the vendor's patch.

## Is CVE-2026-64557 being exploited?

There is no known exploitation of CVE-2026-64557 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-64557 and fix it if it is affected.

What it is: CVE-2026-64557 is a high-severity use after free vulnerability in Linux, published on 29 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-64557 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-64557/ (Markdown: https://insights.sbomify.com/CVE-2026-64557/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64557
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64557
- OSV: https://osv.dev/vulnerability/CVE-2026-64557

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64557/
Summaries are generated and may contain mistakes; the official description above is the record.