# CVE-2026-63948: Bluetooth: L2CAP: fix chan ref leak in l2cap_chan_timeout() on !conn

> A reference leak in the Linux kernel Bluetooth L2CAP module can lead to memory exhaustion and denial of service.

- **Severity:** Not scored
- **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:** 19 Jul 2026
- **Updated:** 19 Jul 2026
- **Also known as:** BELL-CVE-2026-63948, DEBIAN-CVE-2026-63948, GHSA-jg7r-p8w6-9pmq, ROOT-OS-UBUNTU-2204-CVE-2026-63948, UBUNTU-CVE-2026-63948

## What is CVE-2026-63948?

CVE-2026-63948 is a memory corruption vulnerability in Linux, published on 19 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 chan ref leak in l2cap_chan_timeout() on !conn

__set_chan_timer() takes a l2cap_chan reference via l2cap_chan_hold()
before scheduling the delayed work.  The normal path in
l2cap_chan_timeout() drops this reference with l2cap_chan_put() at the
end, but the early return when chan->conn is NULL skips the put,
leaking the reference.

Add the missing l2cap_chan_put() before the early return.

## Which versions are affected by CVE-2026-63948?


## How do I fix CVE-2026-63948?

Apply the vendor's patch.

## Is CVE-2026-63948 being exploited?

There is no known exploitation of CVE-2026-63948 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63948 and fix it if it is affected.

What it is: CVE-2026-63948 is a memory corruption vulnerability in Linux, published on 19 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-2026-63948 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-2026-63948/ (Markdown: https://insights.sbomify.com/CVE-2026-63948/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63948
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63948
- OSV: https://osv.dev/vulnerability/CVE-2026-63948

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63948/
Summaries are generated and may contain mistakes; the official description above is the record.