SEPTEMBER 20, 2026
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Case File

CVE-2026-64557

HIGH · CVSS 8.8 EPSS 0.24%

Source: NVD + CISA KEV + EPSS · Published 2026-07-29 · Last synced 2026-08-28

CyberRota Analysis

AI-Generated

A use-after-free vulnerability exists in the Bluetooth L2CAP implementation of the Linux kernel, specifically within the `l2cap_sock_new_connection_cb()` function. This flaw allows an attacker to exploit the timing of socket operations, potentially leading to arbitrary code execution or system crashes. Organizations using Linux systems with Bluetooth capabilities should prioritize patching this vulnerability to mitigate the risk of exploitation.

CVE
CVE-2026-64557
Severity
HIGH
CVSS
8.8
EPSS
0.24%
Linux

Original NVD Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: Fix use-after-free in l2cap_sock_new_connection_cb() l2cap_sock_new_connection_cb() returned l2cap_pi(sk)->chan after release_sock(parent). Once the parent lock is dropped the newly enqueued child socket sk is reachable via the accept queue, so another task can accept and free it before the callback dereferences sk, resulting in a use-after-free. Rework the ->new_connection() op so the core, rather than the callback, owns the child channel's lifetime. The op now receives a pre-allocated new_chan and returns an errno instead of allocating and returning a channel. l2cap_new_connection() allocates the child channel and links it into the conn list via __l2cap_chan_add() before invoking the callback, so the conn-list reference keeps the channel alive once release_sock(parent) exposes the socket to other tasks. Channel configuration that was duplicated in l2cap_sock_init() and the various new_connection callbacks is consolidated into l2cap_chan_set_defaults(), which now inherits from the parent channel when one is supplied.