Linux: Double Free
CVE-2022-50419 is a high-severity double 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 4bcefec3636208b4c97536b26014d5935d5c10a0, 6144423712d570247b8ca26e50a277c30dd13702, 671fee73e08ff415d36a7c16bdf238927df83884 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 0.24% 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 4bcefec3636208b4c97536b26014d5935d5c10a0 or 6144423712d570247b8ca26e50a277c30dd13702 or 671fee73e08ff415d36a7c16bdf238927df83884 or 6e85d2ad958c6f034b1b158d904019869dbb3c81, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.9.331 or 4.14.296 or 4.19.262 or 5.4.220, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | b219e3ac66183fc9771b94af931fb5fd41d586ec up to, but not including, 4bcefec3636208b4c97536b26014d5935d5c10a0; b219e3ac66183fc9771b94af931fb5fd41d586ec up to, but not including, 6144423712d570247b8ca26e50a277c30dd13702; b219e3ac66183fc9771b94af931fb5fd41d586ec up to, but not including, 671fee73e08ff415d36a7c16bdf238927df83884; b219e3ac66183fc9771b94af931fb5fd41d586ec up to, but not including, 6e85d2ad958c6f034b1b158d904019869dbb3c81; b219e3ac66183fc9771b94af931fb5fd41d586ec up to, but not including, 7b674dce4162bb46d396586e30e4653427023875; b219e3ac66183fc9771b94af931fb5fd41d586ec up to, but not including, 3423a50fa018e88aed4c900d59c3c8334d8ad583; b219e3ac66183fc9771b94af931fb5fd41d586ec up to, but not including, ef055094df4c10b73cfe67c8d43f9de1fb608a8b; b219e3ac66183fc9771b94af931fb5fd41d586ec up to, but not including, 1b6c89571f453101251201f0fad1c26f7256e937; and 2 more ranges | 4bcefec3636208b4c97536b26014d5935d5c10a0, 6144423712d570247b8ca26e50a277c30dd13702, 671fee73e08ff415d36a7c16bdf238927df83884, 6e85d2ad958c6f034b1b158d904019869dbb3c81, 7b674dce4162bb46d396586e30e4653427023875, 3423a50fa018e88aed4c900d59c3c8334d8ad583 |
| Linux | Linux Kernel | 2.6.19 up to, but not including, 4.9.331; 4.10 up to, but not including, 4.14.296; 4.15 up to, but not including, 4.19.262; 4.20 up to, but not including, 5.4.220; 5.5 up to, but not including, 5.10.150; 5.11 up to, but not including, 5.15.75; 5.16 up to, but not including, 5.19.17; 6.0 up to, but not including, 6.0.3 | 4.9.331, 4.14.296, 4.19.262, 5.4.220, 5.10.150, 5.15.75 |
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: hci_sysfs: Fix attempting to call device_add multiple times device_add shall not be called multiple times as stated in its documentation: 'Do not call this routine or device_register() more than once for any device structure' Syzkaller reports a bug as follows [1]: ------------[ cut here ]------------ kernel BUG at lib/list_debug.c:33! invalid opcode: 0000 [#1] PREEMPT SMP KASAN [...] Call Trace: <TASK> __list_add include/linux/list.h:69 [inline] list_add_tail include/linux/list.h:102 [inline] kobj_kset_join lib/kobject.c:164 [inline] kobject_add_internal+0x18f/0x8f0 lib/kobject.c:214 kobject_add_varg lib/kobject.c:358 [inline] kobject_add+0x150/0x1c0 lib/kobject.c:410 device_add+0x368/0x1e90 drivers/base/core.c:3452 hci_conn_add_sysfs+0x9b/0x1b0 net/bluetooth/hci_sysfs.c:53 hci_le_cis_estabilished_evt+0x57c/0xae0 net/bluetooth/hci_event.c:6799 hci_le_meta_evt+0x2b8/0x510 net/bluetooth/hci_event.c:7110 hci_event_func net/bluetooth/hci_event.c:7440 [inline] hci_event_packet+0x63d/0xfd0 net/bluetooth/hci_event.c:7495 hci_rx_work+0xae7/0x1230 net/bluetooth/hci_core.c:4007 process_one_work+0x991/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e4/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 </TASK>
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Double Free
The product calls free() twice on the same memory address.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- Ensure that each allocation is freed only once. After freeing a chunk, set the pointer to NULL to ensure the pointer cannot be freed again. In complicated error conditions, be sure that clean-up routines respect the state of allocation properly. If the language is object oriented, ensure that object destructors delete each chunk of memory only once.
- Use a static analysis tool to find double free instances.
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/1b6c89571f453101251201f0fad1c26f7256e937
- git.kernel.org/stable/c/3423a50fa018e88aed4c900d59c3c8334d8ad583
- git.kernel.org/stable/c/448a496f760664d3e2e79466aa1787e6abc922b5
- git.kernel.org/stable/c/4bcefec3636208b4c97536b26014d5935d5c10a0
- git.kernel.org/stable/c/6144423712d570247b8ca26e50a277c30dd13702
- git.kernel.org/stable/c/671fee73e08ff415d36a7c16bdf238927df83884
- git.kernel.org/stable/c/6e85d2ad958c6f034b1b158d904019869dbb3c81
- git.kernel.org/stable/c/7b674dce4162bb46d396586e30e4653427023875
- git.kernel.org/stable/c/ef055094df4c10b73cfe67c8d43f9de1fb608a8b
Recent Double Free vulnerabilities
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- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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