# CVE-2024-36013: Bluetooth: L2CAP: Fix slab-use-after-free in l2cap_connect()

> A use-after-free flaw in the Linux kernel Bluetooth L2CAP subsystem allows attackers to cause denial of service or execute arbitrary code.

- **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:** 23 May 2024
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2024-36013, DEBIAN-CVE-2024-36013, GHSA-f835-w392-m6qf, ROOT-OS-DEBIAN-11-CVE-2024-36013, ROOT-OS-DEBIAN-12-CVE-2024-36013, ROOT-OS-UBUNTU-2204-CVE-2024-36013, UBUNTU-CVE-2024-36013

## What is CVE-2024-36013?

CVE-2024-36013 is a high-severity use after free vulnerability in Linux kernel, published on 23 May 2024. 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 slab-use-after-free in l2cap_connect()

Extend a critical section to prevent chan from early freeing.
Also make the l2cap_connect() return type void. Nothing is using the
returned value but it is ugly to return a potentially freed pointer.
Making it void will help with backports because earlier kernels did use
the return value. Now the compile will break for kernels where this
patch is not a complete fix.

Call stack summary:

[use]
l2cap_bredr_sig_cmd
  l2cap_connect
  ┌ mutex_lock(&conn->chan_lock);
  │ chan = pchan->ops->new_connection(pchan); <- alloc chan
  │ __l2cap_chan_add(conn, chan);
  │   l2cap_chan_hold(chan);
  │   list_add(&chan->list, &conn->chan_l);   ... (1)
  └ mutex_unlock(&conn->chan_lock);
    chan->conf_state              ... (4) <- use after free

[free]
l2cap_conn_del
┌ mutex_lock(&conn->chan_lock);
│ foreach chan in conn->chan_l:            ... (2)
│   l2cap_chan_put(chan);
│     l2cap_chan_destroy
│       kfree(chan)               ... (3) <- chan freed
└ mutex_unlock(&conn->chan_lock);

==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read
include/linux/instrumented.h:68 [inline]
BUG: KASAN: slab-use-after-free in _test_bit
include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
BUG: KASAN: slab-use-after-free in l2cap_connect+0xa67/0x11a0
net/bluetooth/l2cap_core.c:4260
Read of size 8 at addr ffff88810bf040a0 by task kworker/u3:1/311

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2024-36013?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2024-36013?

Apply the vendor's patch.

## Is CVE-2024-36013 being exploited?

There is no known exploitation of CVE-2024-36013 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-36013 and fix it if it is affected.

What it is: CVE-2024-36013 is a high-severity use after free vulnerability in Linux kernel, published on 23 May 2024. 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-2024-36013 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2024-36013/ (Markdown: https://insights.sbomify.com/CVE-2024-36013/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-36013
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-36013
- OSV: https://osv.dev/vulnerability/CVE-2024-36013

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-36013/
Summaries are generated and may contain mistakes; the official description above is the record.