Linux: Use After Free
CVE-2022-50305 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 b85102a3aa3810a09eb55692e8cd6ffbb304e57d, 390a1a98288a53b2e7555097d83c6e55d579b166, 1b41beaa7a58467505ec3023af8aad74f878b888 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 0.16% 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 b85102a3aa3810a09eb55692e8cd6ffbb304e57d or 390a1a98288a53b2e7555097d83c6e55d579b166 or 1b41beaa7a58467505ec3023af8aad74f878b888 or 6.0.16, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.0.16 or 6.1.2, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | b60ee210a76cabdc2dd5396de299a1860b4945cd up to, but not including, b85102a3aa3810a09eb55692e8cd6ffbb304e57d; 89cdb224f2abe37ec4ac21ba0d9ddeb5a6a9cf68 up to, but not including, 390a1a98288a53b2e7555097d83c6e55d579b166; 89cdb224f2abe37ec4ac21ba0d9ddeb5a6a9cf68 up to, but not including, 1b41beaa7a58467505ec3023af8aad74f878b888; 6.0.11 up to, but not including, 6.0.16; 6.1 | b85102a3aa3810a09eb55692e8cd6ffbb304e57d, 390a1a98288a53b2e7555097d83c6e55d579b166, 1b41beaa7a58467505ec3023af8aad74f878b888, 6.0.16 |
| Linux | Linux Kernel | 6.0.11 up to, but not including, 6.0.16; 6.1.1 up to, but not including, 6.1.2; 6.1 | 6.0.16, 6.1.2 |
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: ASoC: sof_es8336: fix possible use-after-free in sof_es8336_remove() sof_es8336_remove() calls cancel_delayed_work(). However, that function does not wait until the work function finishes. This means that the callback function may still be running after the driver's remove function has finished, which would result in a use-after-free. Fix by calling cancel_delayed_work_sync(), which ensures that the work is properly cancelled, no longer running, and unable to re-schedule itself.
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
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
Spotted an error? Tell us.