Use After Free Affecting kernel-zfcpdump-modules-core package, versions <0:5.14.0-687.47.1.el9_8


Severity

Recommended
high

Based on AlmaLinux security rating.

Threat Intelligence

EPSS
0.25% (17th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-ALMALINUX9-KERNELZFCPDUMPMODULESCORE-19902501
  • published18 Sept 2026
  • disclosed14 Sept 2026

Introduced: 14 Sep 2026

NewCVE-2026-53256  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade AlmaLinux:9 kernel-zfcpdump-modules-core to version 0:5.14.0-687.47.1.el9_8 or higher.
This issue was patched in ALSA-2026:67150.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-zfcpdump-modules-core package and not the kernel-zfcpdump-modules-core package as distributed by AlmaLinux. See How to fix? for AlmaLinux:9 relevant fixed versions and status.

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

Bluetooth: RFCOMM: hold listener socket in rfcomm_connect_ind()

rfcomm_get_sock_by_channel() scans rfcomm_sk_list under the list lock, but returns the selected listener after dropping that lock without taking a reference. rfcomm_connect_ind() then locks the listener, queues a child socket on it, and may notify it after unlocking it.

The buggy scenario involves two paths, with each column showing the order within that path:

rfcomm_connect_ind(): listener close:

  1. Find parent in 1. close() enters rfcomm_get_sock_by_channel() rfcomm_sock_release().
  2. Drop rfcomm_sk_list.lock 2. rfcomm_sock_shutdown() without pinning parent. closes the listener.
  3. Call lock_sock(parent) and 3. rfcomm_sock_kill() bt_accept_enqueue(parent, unlinks and puts parent. sk, true).
  4. Read parent flags and may 4. parent can be freed. call sk_state_change().

If close wins the race, parent can be freed before rfcomm_connect_ind() reaches lock_sock(), bt_accept_enqueue(), or the deferred-setup callback.

Take a reference on the listener before leaving rfcomm_sk_list.lock. After lock_sock() succeeds, recheck that it is still in BT_LISTEN before queueing a child, cache the deferred-setup bit while the parent is locked, and drop the reference after the last parent use.

KASAN reported a slab-use-after-free in lock_sock_nested() from rfcomm_connect_ind(), with the freeing stack going through rfcomm_sock_kill() and rfcomm_sock_release().

CVSS Base Scores

version 3.1