Linux: Use After Free
CVE-2024-53237 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 6894717a1ea363c5a27010ba604f957c309d282d, fb91ce37dc9a37ea23cf32b6d7b667004e93d4c5, a9584c897d1cba6265c78010bbb45ca5722c88bc as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.32% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 6894717a1ea363c5a27010ba604f957c309d282d or fb91ce37dc9a37ea23cf32b6d7b667004e93d4c5 or a9584c897d1cba6265c78010bbb45ca5722c88bc or 0f67ca2a80acf8b207240405b7f72d660665d3df, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.20 or 5.5 or 5.10.231 or 5.15.174, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 3c4236f1b2a715e878a06599fa8b0cc21f165d28 up to, but not including, 6894717a1ea363c5a27010ba604f957c309d282d; 53d61daf35b1bbf3ae06e852ee107aa2f05b3776 up to, but not including, fb91ce37dc9a37ea23cf32b6d7b667004e93d4c5; ba7088769800d9892a7e4f35c3137a5b3e65410b up to, but not including, a9584c897d1cba6265c78010bbb45ca5722c88bc; 87624b1f9b781549e69f92db7ede012a21cec275 up to, but not including, 0f67ca2a80acf8b207240405b7f72d660665d3df; 56a4fdde95ed98d864611155f6728983e199e198 up to, but not including, de5a44f351ca7efd9add9851b218f5353e2224b7; a85fb91e3d728bdfc80833167e8162cce8bc7004 up to, but not including, 91e2a2e4d1336333804cd31162984f01ad8cc70f; a85fb91e3d728bdfc80833167e8162cce8bc7004 up to, but not including, 7b277bd569bb6a2777f0014f84b4344f444fd49d; a85fb91e3d728bdfc80833167e8162cce8bc7004 up to, but not including, 27aabf27fd014ae037cc179c61b0bee7cff55b3d; and 10 more ranges | 6894717a1ea363c5a27010ba604f957c309d282d, fb91ce37dc9a37ea23cf32b6d7b667004e93d4c5, a9584c897d1cba6265c78010bbb45ca5722c88bc, 0f67ca2a80acf8b207240405b7f72d660665d3df, de5a44f351ca7efd9add9851b218f5353e2224b7, 91e2a2e4d1336333804cd31162984f01ad8cc70f |
| Linux | Linux Kernel | 4.19.300 up to, but not including, 4.20; 5.4.262 up to, but not including, 5.5; 5.10.202 up to, but not including, 5.10.231; 5.15.140 up to, but not including, 5.15.174; 6.1.64 up to, but not including, 6.1.120; 6.5.13 up to, but not including, 6.6; 6.6.3 up to, but not including, 6.6.64; 6.7 up to, but not including, 6.11.11; and 1 more ranges | 4.20, 5.5, 5.10.231, 5.15.174, 6.1.120, 6.6 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: fix use-after-free in device_for_each_child() Syzbot has reported the following KASAN splat: BUG: KASAN: slab-use-after-free in device_for_each_child+0x18f/0x1a0 Read of size 8 at addr ffff88801f605308 by task kbnepd bnep0/4980 CPU: 0 UID: 0 PID: 4980 Comm: kbnepd bnep0 Not tainted 6.12.0-rc4-00161-gae90f6a6170d #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x100/0x190 ? device_for_each_child+0x18f/0x1a0 print_report+0x13a/0x4cb ? __virt_addr_valid+0x5e/0x590 ? __phys_addr+0xc6/0x150 ? device_for_each_child+0x18f/0x1a0 kasan_report+0xda/0x110 ? device_for_each_child+0x18f/0x1a0 ? __pfx_dev_memalloc_noio+0x10/0x10 device_for_each_child+0x18f/0x1a0 ? __pfx_device_for_each_child+0x10/0x10 pm_runtime_set_memalloc_noio+0xf2/0x180 netdev_unregister_kobject+0x1ed/0x270 unregister_netdevice_many_notify+0x123c/0x1d80 ? __mutex_trylock_common+0xde/0x250 ? __pfx_unregister_netdevice_many_notify+0x10/0x10 ? trace_contention_end+0xe6/0x140 ? __mutex_lock+0x4e7/0x8f0 ? __pfx_lock_acquire.part.0+0x10/0x10 ? rcu_is_watching+0x12/0xc0 ? unregister_netdev+0x12/0x30 unregister_netdevice_queue+0x30d/0x3f0 ? __pfx_unregister_netdevice_queue+0x10/0x10 ? __pfx_down_write+0x10/0x10 unregister_netdev+0x1c/0x30 bnep_session+0x1fb3/0x2ab0 ? __pfx_bnep_session+0x10/0x10 ? __pfx_lock_release+0x10/0x10 ? __pfx_woken_wake_function+0x10/0x10 ? __kthread_parkme+0x132/0x200 ? __pfx_bnep_session+0x10/0x10 ? kthread+0x13a/0x370 ? __pfx_bnep_session+0x10/0x10 kthread+0x2b7/0x370 ? __pfx_kthread+0x10/0x10 ret_from_fork+0x48/0x80 ? __pfx_kthread+0x10/0x10 ret_from_fork_asm+0x1a/0x30 </TASK> Allocated by task 4974: kasan_save_stack+0x30/0x50 kasan_save_track+0x14/0x30 __kasan_kmalloc+0xaa/0xb0 __kmalloc_noprof+0x1d1/0x440 hci_alloc_dev_priv+0x1d/0x2820 __vhci_create_device+0xef/0x7d0 vhci_write+0x2c7/0x480 vfs_write+0x6a0/0xfc0 ksys_write+0x12f/0x260 do_syscall_64+0xc7/0x250 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 4979: kasan_save_stack+0x30/0x50 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3b/0x60 __kasan_slab_free+0x4f/0x70 kfree+0x141/0x490 hci_release_dev+0x4d9/0x600 bt_host_release+0x6a/0xb0 device_release+0xa4/0x240 kobject_put+0x1ec/0x5a0 put_device+0x1f/0x30 vhci_release+0x81/0xf0 __fput+0x3f6/0xb30 task_work_run+0x151/0x250 do_exit+0xa79/0x2c30 do_group_exit+0xd5/0x2a0 get_signal+0x1fcd/0x2210 arch_do_signal_or_restart+0x93/0x780 syscall_exit_to_user_mode+0x140/0x290 do_syscall_64+0xd4/0x250 entry_SYSCALL_64_after_hwframe+0x77/0x7f In 'hci_conn_del_sysfs()', 'device_unregister()' may be called when an underlying (kobject) reference counter is greater than 1. This means that reparenting (happened when the device is actually freed) is delayed and, during that delay, parent controller device (hciX) may be deleted. Since the latter may create a dangling pointer to freed parent, avoid that scenario by reparenting to NULL explicitly.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/0f67ca2a80acf8b207240405b7f72d660665d3df
- git.kernel.org/stable/c/27aabf27fd014ae037cc179c61b0bee7cff55b3d
- git.kernel.org/stable/c/7b277bd569bb6a2777f0014f84b4344f444fd49d
- git.kernel.org/stable/c/91e2a2e4d1336333804cd31162984f01ad8cc70f
- git.kernel.org/stable/c/a9584c897d1cba6265c78010bbb45ca5722c88bc
- git.kernel.org/stable/c/de5a44f351ca7efd9add9851b218f5353e2224b7
- git.kernel.org/stable/c/fb91ce37dc9a37ea23cf32b6d7b667004e93d4c5
Other references
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.0 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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