🛡️ CVE-2024-36009 — kernel

🟠 CVSS 7.8 — High ✅ No Known Exploit NVD
7.8
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

ax25: Fix netdev refcount issue

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

ax25: Fix netdev refcount issue

The dev_tracker is added to ax25_cb in ax25_bind(). When the

ax25 device is detaching, the dev_tracker of ax25_cb should be

deallocated in ax25_kill_by_device() instead of the dev_tracker

of ax25_dev. The log reported by ref_tracker is shown below:

[ 80.884935] ref_tracker: reference already released.

[ 80.885150] ref_tracker: allocated in:

[ 80.885349] ax25_dev_device_up+0x105/0x540

[ 80.885730] ax25_device_event+0xa4/0x420

[ 80.885730] notifier_call_chain+0xc9/0x1e0

[ 80.885730] __dev_notify_flags+0x138/0x280

[ 80.885730] dev_change_flags+0xd7/0x180

[ 80.885730] dev_ifsioc+0x6a9/0xa30

[ 80.885730] dev_ioctl+0x4d8/0xd90

[ 80.885730] sock_do_ioctl+0x1c2/0x2d0

[ 80.885730] sock_ioctl+0x38b/0x4f0

[ 80.885730] __se_sys_ioctl+0xad/0xf0

[ 80.885730] do_syscall_64+0xc4/0x1b0

[ 80.885730] entry_SYSCALL_64_after_hwframe+0x67/0x6f

[ 80.885730] ref_tracker: freed in:

[ 80.885730] ax25_device_event+0x272/0x420

[ 80.885730] notifier_call_chain+0xc9/0x1e0

[ 80.885730] dev_close_many+0x272/0x370

[ 80.885730] unregister_netdevice_many_notify+0x3b5/0x1180

[ 80.885730] unregister_netdev+0xcf/0x120

[ 80.885730] sixpack_close+0x11f/0x1b0

[ 80.885730] tty_ldisc_kill+0xcb/0x190

[ 80.885730] tty_ldisc_hangup+0x338/0x3d0

[ 80.885730] __tty_hangup+0x504/0x740

[ 80.885730] tty_release+0x46e/0xd80

[ 80.885730] __fput+0x37f/0x770

[ 80.885730] __x64_sys_close+0x7b/0xb0

[ 80.885730] do_syscall_64+0xc4/0x1b0

[ 80.885730] entry_SYSCALL_64_after_hwframe+0x67/0x6f

[ 80.893739] ------------[ cut here ]------------

[ 80.894030] WARNING: CPU: 2 PID: 140 at lib/ref_tracker.c:255 ref_tracker_free+0x47b/0x6b0

[ 80.894297] Modules linked in:

[ 80.894929] CPU: 2 PID: 140 Comm: ax25_conn_rel_6 Not tainted 6.9.0-rc4-g8cd26fd90c1a #11

[ 80.895190] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qem4

[ 80.895514] RIP: 0010:ref_tracker_free+0x47b/0x6b0

[ 80.895808] Code: 83 c5 18 4c 89 eb 48 c1 eb 03 8a 04 13 84 c0 0f 85 df 01 00 00 41 83 7d 00 00 75 4b 4c 89 ff 9

[ 80.896171] RSP: 0018:ffff888009edf8c0 EFLAGS: 00000286

[ 80.896339] RAX: 1ffff1100141ac00 RBX: 1ffff1100149463b RCX: dffffc0000000000

[ 80.896502] RDX: 0000000000000001 RSI: 0000000000000246 RDI: ffff88800a0d6518

[ 80.896925] RBP: ffff888009edf9b0 R08: ffff88806d3288d3 R09: 1ffff1100da6511a

[ 80.897212] R10: dffffc0000000000 R11: ffffed100da6511b R12: ffff88800a4a31d4

[ 80.897859] R13: ffff88800a4a31d8 R14: dffffc0000000000 R15: ffff88800a0d6518

[ 80.898279] FS: 00007fd88b7fe700(0000) GS:ffff88806d300000(0000) knlGS:0000000000000000

[ 80.899436] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

[ 80.900181] CR2: 00007fd88c001d48 CR3: 000000000993e000 CR4: 00000000000006f0

...

[ 80.935774] ref_tracker: sp%d@000000000bb9df3d has 1/1 users at

[ 80.935774] ax25_bind+0x424/0x4e0

[ 80.935774] __sys_bind+0x1d9/0x270

[ 80.935774] __x64_sys_bind+0x75/0x80

[ 80.935774] do_syscall_64+0xc4/0x1b0

[ 80.935774] entry_SYSCALL_64_after_hwframe+0x67/0x6f

Change ax25_dev->dev_tracker to the dev_tracker of ax25_cb

in order to mitigate the bug.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs low-level privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability high.

Affected software

CVE-2024-36009 is recorded against 2 packages.

  • kernel (from 6.7.0 up to 6.8.9)
  • linux-kernel

Timeline and source

Published on 20 May 2024 and last revised on 6 August 2026. No public exploit is currently recorded for this entry. A vendor advisory or fix has been published. Record sourced from NVD.

References

www.openwall.com (Web)
www.openwall.com (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
git.kernel.org (Web)
github.com (Advisory)
nvd.nist.gov (Advisory)
git.kernel.org (Package)

CVE-2024-36009 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

Details

Severity High
CVSS Score 7.8
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2024-05-20
Updated 2026-08-12
Modified 2026-08-06

Affected Packages

Software From version Fixed in
kernel 6.7.0 6.8.9
linux-kernel — —

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