Linux: Use After Free
CVE-2023-53082 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 baafa2960731211837d8fc04ff3873ecb7440464, fa1f327f93c9a7310cce9d2fcda28b7af91f7437, aed8efddd39b3434c96718d39009285c52b1cafc 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 0.2% 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 baafa2960731211837d8fc04ff3873ecb7440464 or fa1f327f93c9a7310cce9d2fcda28b7af91f7437 or aed8efddd39b3434c96718d39009285c52b1cafc, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.1.21 or 6.2.8, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | ffbda8e9df10d1784d5427ec199e7d8308e3763f up to, but not including, baafa2960731211837d8fc04ff3873ecb7440464; ffbda8e9df10d1784d5427ec199e7d8308e3763f up to, but not including, fa1f327f93c9a7310cce9d2fcda28b7af91f7437; ffbda8e9df10d1784d5427ec199e7d8308e3763f up to, but not including, aed8efddd39b3434c96718d39009285c52b1cafc; 5.19 | baafa2960731211837d8fc04ff3873ecb7440464, fa1f327f93c9a7310cce9d2fcda28b7af91f7437, aed8efddd39b3434c96718d39009285c52b1cafc |
| Linux | Linux Kernel | 5.19 up to, but not including, 6.1.21; 6.2 up to, but not including, 6.2.8; 6.3 | 6.1.21, 6.2.8 |
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.
Official description
In the Linux kernel, the following vulnerability has been resolved: vp_vdpa: fix the crash in hot unplug with vp_vdpa While unplugging the vp_vdpa device, it triggers a kernel panic The root cause is: vdpa_mgmtdev_unregister() will accesses modern devices which will cause a use after free. So need to change the sequence in vp_vdpa_remove [ 195.003359] BUG: unable to handle page fault for address: ff4e8beb80199014 [ 195.004012] #PF: supervisor read access in kernel mode [ 195.004486] #PF: error_code(0x0000) - not-present page [ 195.004960] PGD 100000067 P4D 1001b6067 PUD 1001b7067 PMD 1001b8067 PTE 0 [ 195.005578] Oops: 0000 1 PREEMPT SMP PTI [ 195.005968] CPU: 13 PID: 164 Comm: kworker/u56:10 Kdump: loaded Not tainted 5.14.0-252.el9.x86_64 #1 [ 195.006792] Hardware name: Red Hat KVM/RHEL, BIOS edk2-20221207gitfff6d81270b5-2.el9 unknown [ 195.007556] Workqueue: kacpi_hotplug acpi_hotplug_work_fn [ 195.008059] RIP: 0010:ioread8+0x31/0x80 [ 195.008418] Code: 77 28 48 81 ff 00 00 01 00 76 0b 89 fa ec 0f b6 c0 c3 cc cc cc cc 8b 15 ad 72 93 01 b8 ff 00 00 00 85 d2 75 0f c3 cc cc cc cc <8a> 07 0f b6 c0 c3 cc cc cc cc 83 ea 01 48 83 ec 08 48 89 fe 48 c7 [ 195.010104] RSP: 0018:ff4e8beb8067bab8 EFLAGS: 00010292 [ 195.010584] RAX: ffffffffc05834a0 RBX: ffffffffc05843c0 RCX: ff4e8beb8067bae0 [ 195.011233] RDX: ff1bcbd580f88000 RSI: 0000000000000246 RDI: ff4e8beb80199014 [ 195.011881] RBP: ff1bcbd587e39000 R08: ffffffff916fa2d0 R09: ff4e8beb8067ba68 [ 195.012527] R10: 000000000000001c R11: 0000000000000000 R12: ff1bcbd5a3de9120 [ 195.013179] R13: ffffffffc062d000 R14: 0000000000000080 R15: ff1bcbe402bc7805 [ 195.013826] FS: 0000000000000000(0000) GS:ff1bcbe402740000(0000) knlGS:0000000000000000 [ 195.014564] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 195.015093] CR2: ff4e8beb80199014 CR3: 0000000107dea002 CR4: 0000000000771ee0 [ 195.015741] PKRU: 55555554 [ 195.016001] Call Trace: [ 195.016233] <TASK> [ 195.016434] vp_modern_get_status+0x12/0x20 [ 195.016823] vp_vdpa_reset+0x1b/0x50 [vp_vdpa] [ 195.017238] virtio_vdpa_reset+0x3c/0x48 [virtio_vdpa] [ 195.017709] remove_vq_common+0x1f/0x3a0 [virtio_net] [ 195.018178] virtnet_remove+0x5d/0x70 [virtio_net] [ 195.018618] virtio_dev_remove+0x3d/0x90 [ 195.018986] device_release_driver_internal+0x1aa/0x230 [ 195.019466] bus_remove_device+0xd8/0x150 [ 195.019841] device_del+0x18b/0x3f0 [ 195.020167] ? kernfs_find_ns+0x35/0xd0 [ 195.020526] device_unregister+0x13/0x60 [ 195.020894] unregister_virtio_device+0x11/0x20 [ 195.021311] device_release_driver_internal+0x1aa/0x230 [ 195.021790] bus_remove_device+0xd8/0x150 [ 195.022162] device_del+0x18b/0x3f0 [ 195.022487] device_unregister+0x13/0x60 [ 195.022852] ? vdpa_dev_remove+0x30/0x30 [vdpa] [ 195.023270] vp_vdpa_dev_del+0x12/0x20 [vp_vdpa] [ 195.023694] vdpa_match_remove+0x2b/0x40 [vdpa] [ 195.024115] bus_for_each_dev+0x78/0xc0 [ 195.024471] vdpa_mgmtdev_unregister+0x65/0x80 [vdpa] [ 195.024937] vp_vdpa_remove+0x23/0x40 [vp_vdpa] [ 195.025353] pci_device_remove+0x36/0xa0 [ 195.025719] device_release_driver_internal+0x1aa/0x230 [ 195.026201] pci_stop_bus_device+0x6c/0x90 [ 195.026580] pci_stop_and_remove_bus_device+0xe/0x20 [ 195.027039] disable_slot+0x49/0x90 [ 195.027366] acpiphp_disable_and_eject_slot+0x15/0x90 [ 195.027832] hotplug_event+0xea/0x210 [ 195.028171] ? hotplug_event+0x210/0x210 [ 195.028535] acpiphp_hotplug_notify+0x22/0x80 [ 195.028942] ? hotplug_event+0x210/0x210 [ 195.029303] acpi_device_hotplug+0x8a/0x1d0 [ 195.029690] acpi_hotplug_work_fn+0x1a/0x30 [ 195.030077] process_one_work+0x1e8/0x3c0 [ 195.030451] worker_thread+0x50/0x3b0 [ 195.030791] ? rescuer_thread+0x3a0/0x3a0 [ 195.031165] kthread+0xd9/0x100 [ 195.031459] ? kthread_complete_and_exit+0x20/0x20 [ 195.031899] ret_from_fork+0x22/0x30 [ 195.032233] </TASK>
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: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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