Linux: Use After Free
CVE-2022-50192 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 415b4ce61308f24583912d887772dfcbf97f1d20, 800c7767e05d29656713e04532823a752e57e037, 67f77172644260482fdafc03b6025847944701e5 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 0.27% 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 415b4ce61308f24583912d887772dfcbf97f1d20 or 800c7767e05d29656713e04532823a752e57e037 or 67f77172644260482fdafc03b6025847944701e5 or 7e9984d183bb1e99e766c5c2b950ff21f7f7b6c0, whichever matches your release line, or a later version.
- Update Linux Kernel to 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 | 26c863418221344b1cfb8e6c11116b2b81144281 up to, but not including, 415b4ce61308f24583912d887772dfcbf97f1d20; 26c863418221344b1cfb8e6c11116b2b81144281 up to, but not including, 800c7767e05d29656713e04532823a752e57e037; 26c863418221344b1cfb8e6c11116b2b81144281 up to, but not including, 67f77172644260482fdafc03b6025847944701e5; 26c863418221344b1cfb8e6c11116b2b81144281 up to, but not including, 7e9984d183bb1e99e766c5c2b950ff21f7f7b6c0; 5.15 | 415b4ce61308f24583912d887772dfcbf97f1d20, 800c7767e05d29656713e04532823a752e57e037, 67f77172644260482fdafc03b6025847944701e5, 7e9984d183bb1e99e766c5c2b950ff21f7f7b6c0 |
| Linux | Linux Kernel | 5.15 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 | 5.15.61, 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.
Official description
In the Linux kernel, the following vulnerability has been resolved: spi: tegra20-slink: fix UAF in tegra_slink_remove() After calling spi_unregister_master(), the refcount of master will be decrease to 0, and it will be freed in spi_controller_release(), the device data also will be freed, so it will lead a UAF when using 'tspi'. To fix this, get the master before unregister and put it when finish using it.
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
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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