# CVE-2026-63976: Bluetooth: l2cap: clear chan->ident on ECRED reconfiguration success

> A remote attacker can cause a denial of service by replaying a failure response with a stale identifier, leading to the destruction of an established Bluetooth channel.

- **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:** 19 Jul 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-63976, DEBIAN-CVE-2026-63976, GHSA-2c97-7qvf-wx4v, ROOT-OS-UBUNTU-2204-CVE-2026-63976, UBUNTU-CVE-2026-63976

## What is CVE-2026-63976?

CVE-2026-63976 is a high-severity denial of service 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: clear chan->ident on ECRED reconfiguration success

l2cap_ecred_reconf_rsp() returns early on success without clearing
chan->ident. Every other L2CAP response handler (l2cap_ecred_conn_rsp,
l2cap_le_connect_rsp, l2cap_config_rsp) clears chan->ident after a
successful transaction to prevent the channel from matching subsequent
responses with the recycled ident value.

A remote attacker that completed a reconfiguration as the peer can
replay a failure response with the stale ident, causing the kernel to
match and destroy the already-established channel via
l2cap_chan_del(chan, ECONNRESET).

Clear chan->ident for all matching channels on success, and harden the
failure path by using l2cap_chan_hold_unless_zero() consistent with
other L2CAP handlers (l2cap_le_command_rej, __l2cap_get_chan_by_ident).

Weakness: CWE-694 (Use of Multiple Resources with Duplicate Identifier)

## Which versions are affected by CVE-2026-63976?


## How do I fix CVE-2026-63976?

Apply the vendor's patch.

## Is CVE-2026-63976 being exploited?

There is no known exploitation of CVE-2026-63976 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63976 and fix it if it is affected.

What it is: CVE-2026-63976 is a high-severity denial of service 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-2026-63976 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-2026-63976/ (Markdown: https://insights.sbomify.com/CVE-2026-63976/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63976
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63976
- OSV: https://osv.dev/vulnerability/CVE-2026-63976

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63976/
Summaries are generated and may contain mistakes; the official description above is the record.