Linux: Use After Free
CVE-2024-26892 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 c7dd42fbebcfb02bef070fd48f774d6412d0b49d, bfe1adf1606f76c180324e53b130f0e76d5cc6c3, bfeaef901194c5923ce3330272786eff2fac513a 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 0.23% 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 c7dd42fbebcfb02bef070fd48f774d6412d0b49d or bfe1adf1606f76c180324e53b130f0e76d5cc6c3 or bfeaef901194c5923ce3330272786eff2fac513a or c957280ef6ab6bdf559a91ae693a6b34310697e3, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.3 or 6.6.23 or 6.7.11 or 6.8.2, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 9270270d62191b7549296721e8d5f3dc0df01563 up to, but not including, c7dd42fbebcfb02bef070fd48f774d6412d0b49d; 9270270d62191b7549296721e8d5f3dc0df01563 up to, but not including, bfe1adf1606f76c180324e53b130f0e76d5cc6c3; 9270270d62191b7549296721e8d5f3dc0df01563 up to, but not including, bfeaef901194c5923ce3330272786eff2fac513a; 9270270d62191b7549296721e8d5f3dc0df01563 up to, but not including, c957280ef6ab6bdf559a91ae693a6b34310697e3; a76eaaaafd8b408238d7865bbbbd311f08988f3d; 95e41ac30a0d0b3637f0b3c93235a7a107a2fb7f; 6.2.15 up to, but not including, 6.3; 6.3.2 up to, but not including, 6.4; and 1 more ranges | c7dd42fbebcfb02bef070fd48f774d6412d0b49d, bfe1adf1606f76c180324e53b130f0e76d5cc6c3, bfeaef901194c5923ce3330272786eff2fac513a, c957280ef6ab6bdf559a91ae693a6b34310697e3, 6.3, 6.4 |
| Linux | Linux Kernel | 6.2.15 up to, but not including, 6.3; 6.3.2 up to, but not including, 6.6.23; 6.7 up to, but not including, 6.7.11; 6.8 up to, but not including, 6.8.2 | 6.3, 6.6.23, 6.7.11, 6.8.2 |
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: wifi: mt76: mt7921e: fix use-after-free in free_irq() From commit a304e1b82808 ("[PATCH] Debug shared irqs"), there is a test to make sure the shared irq handler should be able to handle the unexpected event after deregistration. For this case, let's apply MT76_REMOVED flag to indicate the device was removed and do not run into the resource access anymore. BUG: KASAN: use-after-free in mt7921_irq_handler+0xd8/0x100 [mt7921e] Read of size 8 at addr ffff88824a7d3b78 by task rmmod/11115 CPU: 28 PID: 11115 Comm: rmmod Tainted: G W L 5.17.0 #10 Hardware name: Micro-Star International Co., Ltd. MS-7D73/MPG B650I EDGE WIFI (MS-7D73), BIOS 1.81 01/05/2024 Call Trace: <TASK> dump_stack_lvl+0x6f/0xa0 print_address_description.constprop.0+0x1f/0x190 ? mt7921_irq_handler+0xd8/0x100 [mt7921e] ? mt7921_irq_handler+0xd8/0x100 [mt7921e] kasan_report.cold+0x7f/0x11b ? mt7921_irq_handler+0xd8/0x100 [mt7921e] mt7921_irq_handler+0xd8/0x100 [mt7921e] free_irq+0x627/0xaa0 devm_free_irq+0x94/0xd0 ? devm_request_any_context_irq+0x160/0x160 ? kobject_put+0x18d/0x4a0 mt7921_pci_remove+0x153/0x190 [mt7921e] pci_device_remove+0xa2/0x1d0 __device_release_driver+0x346/0x6e0 driver_detach+0x1ef/0x2c0 bus_remove_driver+0xe7/0x2d0 ? __check_object_size+0x57/0x310 pci_unregister_driver+0x26/0x250 __do_sys_delete_module+0x307/0x510 ? free_module+0x6a0/0x6a0 ? fpregs_assert_state_consistent+0x4b/0xb0 ? rcu_read_lock_sched_held+0x10/0x70 ? syscall_enter_from_user_mode+0x20/0x70 ? trace_hardirqs_on+0x1c/0x130 do_syscall_64+0x5c/0x80 ? trace_hardirqs_on_prepare+0x72/0x160 ? do_syscall_64+0x68/0x80 ? trace_hardirqs_on_prepare+0x72/0x160 entry_SYSCALL_64_after_hwframe+0x44/0xae
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
- 7.0 High severity
- 7.8 High severity
- 7.8 High severity
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