CVE-2024-56654: Bluetooth: hci_event: Fix using rcu_read_(un)lock while iterating

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-12-27 · updated 2026-08-04

Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_event: Fix using rcu_read_(un)lock while iterating The usage of rcu_read_(un)lock while inside list_for_each_entry_rcu is not safe since for the most part entries fetched this way shall be treated as rcu_dereference: Note that the value returned by rcu_dereference() is valid only within the enclosing RCU read-side critical section [1]_. For example, the following is **not** legal:: rcu_read_lock(); p = rcu_dereference(head.next); rcu_read_unlock(); x = p->address; /* BUG!!! */ rcu_read_lock(); y = p->data; /* BUG!!! */ rcu_read_unlock();

Affected products

Linux kernel: from 6.4.16 before 6.5; from 6.5.3 before 6.6.67; from 6.7 before 6.12.6; 6.13-rc1, 6.13-rc2 — fixed in 6.12.6, 6.5, 6.6.67

How to fix

Upgrade to a fixed version: Linux kernel 6.12.6, 6.5, 6.6.67. Check the vendor advisory for mitigations.

References

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