# CVE-2026-74536: Bluetooth: ISO: fix leaking sk after socket release

> A memory leak in the Linux kernel Bluetooth ISO subsystem allows attackers to cause denial of service by exhausting kernel memory.

- **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:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-74536, DEBIAN-CVE-2026-74536, GHSA-8vqw-g268-q22j, UBUNTU-CVE-2026-74536

## What is CVE-2026-74536?

CVE-2026-74536 is a memory corruption vulnerability in Linux, published on 15 Aug 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: ISO: fix leaking sk after socket release

iso_sock_kill() tests !sock_flag(sk, SOCK_ZAPPED) || sk->sk_socket ||
sock_flag(sk, SOCK_DEAD) for early return, but this is always true since
sock_orphan(sk) sets SOCK_DEAD, so the sk reference released by socket
always leaks, iso_sock_destruct is never called.

The socket reference also leaks when __iso_sock_close() does not set
SOCK_ZAPPED, since iso_conn_del() does not call iso_sock_kill() after
zapping.

Fix by replacing SOCK_DEAD by BT_SK_KILLED flag that is not used for
something else, and lock_sock to ensure iso_sock_kill() puts sk only
after socket release only once. Release and iso_conn_del may run
concurrently. Call iso_sock_kill() from iso_conn_del() to clean sk up
after zapping.

Remove call to iso_sock_kill() from iso_sock_close(), as it's generally
no-op there.

## Which versions are affected by CVE-2026-74536?


## How do I fix CVE-2026-74536?

Apply the vendor's patch.

## Is CVE-2026-74536 being exploited?

There is no known exploitation of CVE-2026-74536 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74536 and fix it if it is affected.

What it is: CVE-2026-74536 is a memory corruption vulnerability in Linux, published on 15 Aug 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-2026-74536 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-2026-74536/ (Markdown: https://insights.sbomify.com/CVE-2026-74536/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74536
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74536
- OSV: https://osv.dev/vulnerability/CVE-2026-74536

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74536/
Summaries are generated and may contain mistakes; the official description above is the record.