# CVE-2026-31408: Bluetooth: SCO: Fix use-after-free in sco_recv_frame() due to missing sock_hold

> A use-after-free in the Linux kernel Bluetooth SCO module allows attackers to execute arbitrary code or escalate privileges via concurrent socket operations.

- **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:** 6 Apr 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-81870, BELL-CVE-2026-31408, DEBIAN-CVE-2026-31408, GHSA-82h6-xw4j-pq2m, ROOT-OS-DEBIAN-11-CVE-2026-31408, ROOT-OS-DEBIAN-12-CVE-2026-31408, ROOT-OS-DEBIAN-13-CVE-2026-31408, ROOT-OS-UBUNTU-2204-CVE-2026-31408, ROOT-OS-UBUNTU-2404-CVE-2026-31408, UBUNTU-CVE-2026-31408

## What is CVE-2026-31408?

CVE-2026-31408 is a high-severity use after free vulnerability in Linux kernel, published on 6 Apr 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: SCO: Fix use-after-free in sco_recv_frame() due to missing sock_hold

sco_recv_frame() reads conn->sk under sco_conn_lock() but immediately
releases the lock without holding a reference to the socket. A concurrent
close() can free the socket between the lock release and the subsequent
sk->sk_state access, resulting in a use-after-free.

Other functions in the same file (sco_sock_timeout(), sco_conn_del())
correctly use sco_sock_hold() to safely hold a reference under the lock.

Fix by using sco_sock_hold() to take a reference before releasing the
lock, and adding sock_put() on all exit paths.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2026-31408?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31408?

Apply the vendor's patch.

## Is CVE-2026-31408 being exploited?

There is no known exploitation of CVE-2026-31408 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-2026-31408 and fix it if it is affected.

What it is: CVE-2026-31408 is a high-severity use after free vulnerability in Linux kernel, published on 6 Apr 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-2026-31408 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-2026-31408/ (Markdown: https://insights.sbomify.com/CVE-2026-31408/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31408
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31408
- OSV: https://osv.dev/vulnerability/CVE-2026-31408

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31408/
Summaries are generated and may contain mistakes; the official description above is the record.