---
cve: "CVE-2026-89774"
severity: "HIGH"
cvss: 8.8
epss: "19%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-09-16 09:17:07"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-18T03:45:49+02:00"
---

# CVE-2026-89774

> 8.8 HIGH

## Beschreibung

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.

## CVSS-Vektor

```
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Benachbart | warn |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- Kernel ≥ 5.15.212
- Kernel ≥ 6.1.178
- Kernel ≥ 6.6.145
- Kernel ≥ 6.12.97
- Kernel ≥ 6.18.40

## Referenzen

- <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>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-89774) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_