# CVE-2026-98107: Bluetooth: L2CAP: fix out-of-bounds write in l2cap_ecred_connect

> An out-of-bounds write in the Linux kernel Bluetooth L2CAP module allows attackers to cause memory corruption, potentially leading to code execution or system crashes.

- **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:** 25 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-104804, BELL-CVE-2026-98107, DEBIAN-CVE-2026-98107, GHSA-vgxx-7qq2-4hrv, UBUNTU-CVE-2026-98107

## What is CVE-2026-98107?

CVE-2026-98107 is a memory corruption vulnerability in Linux, published on 25 Sep 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 out-of-bounds write in l2cap_ecred_connect

l2cap_chan_connect() tries to ensure there are no more than
L2CAP_ECRED_CONN_SCID_MAX pending ECRED channels, so they fit in the
same L2CAP_ECRED_CONN_REQ that l2cap_ecred_connect() constructs.

However, the check only counts deferred channels.  If 6 L2CAP sockets
are connected at the same time in order DDDDND (D=deferred,
N=non-deferred), the last can bump the total to max+1.  It results to
one __le16 written out of bounds of the scid array, and an invalid
ECRED_CONN_REQ being sent.

Fix by leaving room for the non-deferred pending ECRED channels in the
counting in l2cap_chan_connect(), so the limit can't be exceeded.

Move counting under same critical section where the channel is added.
Although race conditions involving this appear unreachable, it's easier
to see.

Also add WARN_ON_ONCE check in l2cap_ecred_defer_connect() to make this
less brittle.

## Which versions are affected by CVE-2026-98107?


## How do I fix CVE-2026-98107?

Apply the vendor's patch.

## Is CVE-2026-98107 being exploited?

There is no known exploitation of CVE-2026-98107 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98107 and fix it if it is affected.

What it is: CVE-2026-98107 is a memory corruption vulnerability in Linux, published on 25 Sep 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-2026-98107 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-2026-98107/ (Markdown: https://insights.sbomify.com/CVE-2026-98107/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98107
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98107
- OSV: https://osv.dev/vulnerability/CVE-2026-98107

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98107/
Summaries are generated and may contain mistakes; the official description above is the record.