Linux: Use After Free
CVE-2022-50129 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 de95b52d9aabc979166aba81ccbe623aaf9c16a1, e60d7e2462bf57273563c4e00dbfa79ee973b9e2, 4ee8c39968a648d58b273582d4b021044a41ee5e 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 de95b52d9aabc979166aba81ccbe623aaf9c16a1 or e60d7e2462bf57273563c4e00dbfa79ee973b9e2 or 4ee8c39968a648d58b273582d4b021044a41ee5e or 388326bb1c32fcd09371c1d494af71471ef3a04b, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.137 or 5.15.61 or 5.18.18 or 5.19.2, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | a42d985bd5b234da8b61347a78dc3057bf7bb94d up to, but not including, de95b52d9aabc979166aba81ccbe623aaf9c16a1; a42d985bd5b234da8b61347a78dc3057bf7bb94d up to, but not including, e60d7e2462bf57273563c4e00dbfa79ee973b9e2; a42d985bd5b234da8b61347a78dc3057bf7bb94d up to, but not including, 4ee8c39968a648d58b273582d4b021044a41ee5e; a42d985bd5b234da8b61347a78dc3057bf7bb94d up to, but not including, 388326bb1c32fcd09371c1d494af71471ef3a04b; a42d985bd5b234da8b61347a78dc3057bf7bb94d up to, but not including, b5605148e6ce36bb21020d49010b617693933128; 3.3 | de95b52d9aabc979166aba81ccbe623aaf9c16a1, e60d7e2462bf57273563c4e00dbfa79ee973b9e2, 4ee8c39968a648d58b273582d4b021044a41ee5e, 388326bb1c32fcd09371c1d494af71471ef3a04b, b5605148e6ce36bb21020d49010b617693933128 |
| Linux | Linux Kernel | 3.3 up to, but not including, 5.10.137; 5.11 up to, but not including, 5.15.61; 5.16 up to, but not including, 5.18.18; 5.19 up to, but not including, 5.19.2 | 5.10.137, 5.15.61, 5.18.18, 5.19.2 |
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.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.0 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: RDMA/srpt: Fix a use-after-free Change the LIO port members inside struct srpt_port from regular members into pointers. Allocate the LIO port data structures from inside srpt_make_tport() and free these from inside srpt_make_tport(). Keep struct srpt_device as long as either an RDMA port or a LIO target port is associated with it. This patch decouples the lifetime of struct srpt_port (controlled by the RDMA core) and struct srpt_port_id (controlled by LIO). This patch fixes the following KASAN complaint: BUG: KASAN: use-after-free in srpt_enable_tpg+0x31/0x70 [ib_srpt] Read of size 8 at addr ffff888141cc34b8 by task check/5093 Call Trace: <TASK> show_stack+0x4e/0x53 dump_stack_lvl+0x51/0x66 print_address_description.constprop.0.cold+0xea/0x41e print_report.cold+0x90/0x205 kasan_report+0xb9/0xf0 __asan_load8+0x69/0x90 srpt_enable_tpg+0x31/0x70 [ib_srpt] target_fabric_tpg_base_enable_store+0xe2/0x140 [target_core_mod] configfs_write_iter+0x18b/0x210 new_sync_write+0x1f2/0x2f0 vfs_write+0x3e3/0x540 ksys_write+0xbb/0x140 __x64_sys_write+0x42/0x50 do_syscall_64+0x34/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 </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.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/388326bb1c32fcd09371c1d494af71471ef3a04b
- git.kernel.org/stable/c/4ee8c39968a648d58b273582d4b021044a41ee5e
- git.kernel.org/stable/c/b5605148e6ce36bb21020d49010b617693933128
- git.kernel.org/stable/c/de95b52d9aabc979166aba81ccbe623aaf9c16a1
- git.kernel.org/stable/c/e60d7e2462bf57273563c4e00dbfa79ee973b9e2
Recent Use After Free vulnerabilities
- 8.8 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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