---
cve: "CVE-2026-90256"
severity: "HIGH"
cvss: 8.8
epss: "0.3%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-09-17 17:17:21"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-21T10:07:17+02:00"
---

# CVE-2026-90256

> 8.8 HIGH

## Beschreibung

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: L2CAP: use proto_lock for l2cap_data to fix l2cap_disconn_ind

hci_conn::l2cap_data is accessed without locks in l2cap_disconn_ind via
hci_conn_timeout (disc_work) -> hci_proto_disconn_ind ->
l2cap_disconn_ind.  This is UAF if the l2cap_conn is deleted
concurrently.

disc_work is disabled sync in hci_conn_del(), so we cannot take
hci_dev_lock in disc_work.

Fix by using proto_lock to guard l2cap_data, in addition to hdev->lock
which is held in other access paths.

## 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 ≥ 7.2.6

## Referenzen

- <https://git.kernel.org/stable/c/b495a3a9b33bc4e4613e685bf5c96c136caa22d8>
- <https://git.kernel.org/stable/c/2b66c83ff1751d6bd3201b3017206262ab46dc05>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-90256) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_