Linux: Use After Free
CVE-2022-48686 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 19816a0214684f70b49b25075ff8c402fdd611d3, 5914fa32ef1b7766fea933f9eed94ac5c00aa7ff, 13c80a6c112467bab5e44d090767930555fc17a5 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 0.7% chance of exploitation within 30 days, higher than 54% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 19816a0214684f70b49b25075ff8c402fdd611d3 or 5914fa32ef1b7766fea933f9eed94ac5c00aa7ff or 13c80a6c112467bab5e44d090767930555fc17a5 or c3eb461aa56e6fa94fb80442ba2586bd223a8886, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.4.213 or 5.10.143 or 5.15.68 or 5.19.9, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 3f2304f8c6d6ed97849057bd16fee99e434ca796 up to, but not including, 19816a0214684f70b49b25075ff8c402fdd611d3; 3f2304f8c6d6ed97849057bd16fee99e434ca796 up to, but not including, 5914fa32ef1b7766fea933f9eed94ac5c00aa7ff; 3f2304f8c6d6ed97849057bd16fee99e434ca796 up to, but not including, 13c80a6c112467bab5e44d090767930555fc17a5; 3f2304f8c6d6ed97849057bd16fee99e434ca796 up to, but not including, c3eb461aa56e6fa94fb80442ba2586bd223a8886; 3f2304f8c6d6ed97849057bd16fee99e434ca796 up to, but not including, 160f3549a907a50e51a8518678ba2dcf2541abea; 5.0 | 19816a0214684f70b49b25075ff8c402fdd611d3, 5914fa32ef1b7766fea933f9eed94ac5c00aa7ff, 13c80a6c112467bab5e44d090767930555fc17a5, c3eb461aa56e6fa94fb80442ba2586bd223a8886, 160f3549a907a50e51a8518678ba2dcf2541abea |
| Linux | Linux Kernel | 5.0 up to, but not including, 5.4.213; 5.5 up to, but not including, 5.10.143; 5.11 up to, but not including, 5.15.68; 5.16 up to, but not including, 5.19.9 | 5.4.213, 5.10.143, 5.15.68, 5.19.9 |
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 | 9.8 | Critical | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
| CVSS 3.1 | 6.2 | Medium | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: nvme-tcp: fix UAF when detecting digest errors We should also bail from the io_work loop when we set rd_enabled to true, so we don't attempt to read data from the socket when the TCP stream is already out-of-sync or corrupted.
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
- git.kernel.org/stable/c/13c80a6c112467bab5e44d090767930555fc17a5
- git.kernel.org/stable/c/160f3549a907a50e51a8518678ba2dcf2541abea
- git.kernel.org/stable/c/19816a0214684f70b49b25075ff8c402fdd611d3
- git.kernel.org/stable/c/5914fa32ef1b7766fea933f9eed94ac5c00aa7ff
- git.kernel.org/stable/c/c3eb461aa56e6fa94fb80442ba2586bd223a8886
Recent Use After Free vulnerabilities
- 7.8 High severity
- 9.8 Critical severity
- 7.8 High severity
- 7.8 High severity
- 7.4 High severity
- 9.8 Critical severity
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