Linux: Use After Free
CVE-2022-49426 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 fc90f13ea0dcd960e5002d204fa55cec4e0db2fa, e3cbbdbff8a4db5d053c53fd71be62ccccdb52b0, 9aa215450888cf29af0c479e14a712dc6b0c506c 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 0.29% 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 fc90f13ea0dcd960e5002d204fa55cec4e0db2fa or e3cbbdbff8a4db5d053c53fd71be62ccccdb52b0 or 9aa215450888cf29af0c479e14a712dc6b0c506c or cbd23144f7662b00bcde32a938c4a4057e476d68, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.15.46 or 5.17.14 or 5.18.3, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 32784a9562fb0518b12e9797ee2aec52214adf6f up to, but not including, fc90f13ea0dcd960e5002d204fa55cec4e0db2fa; 32784a9562fb0518b12e9797ee2aec52214adf6f up to, but not including, e3cbbdbff8a4db5d053c53fd71be62ccccdb52b0; 32784a9562fb0518b12e9797ee2aec52214adf6f up to, but not including, 9aa215450888cf29af0c479e14a712dc6b0c506c; 32784a9562fb0518b12e9797ee2aec52214adf6f up to, but not including, cbd23144f7662b00bcde32a938c4a4057e476d68; 5.11 | fc90f13ea0dcd960e5002d204fa55cec4e0db2fa, e3cbbdbff8a4db5d053c53fd71be62ccccdb52b0, 9aa215450888cf29af0c479e14a712dc6b0c506c, cbd23144f7662b00bcde32a938c4a4057e476d68 |
| Linux | Linux Kernel | 5.11 up to, but not including, 5.15.46; 5.16 up to, but not including, 5.17.14; 5.18 up to, but not including, 5.18.3 | 5.15.46, 5.17.14, 5.18.3 |
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 CISA (ADP).
Official description
In the Linux kernel, the following vulnerability has been resolved: iommu/arm-smmu-v3-sva: Fix mm use-after-free We currently call arm64_mm_context_put() without holding a reference to the mm, which can result in use-after-free. Call mmgrab()/mmdrop() to ensure the mm only gets freed after we unpinned the ASID.
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: total).
- 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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