Linux: Use After Free
CVE-2022-50087 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 5aa558232edc30468d1f35108826dd5b3ffe978f, 18048cba444a7c41dbf42c180d6b46606fc24c51, 08272646cd7c310642c39b7f54348fddd7987643 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 0.21% 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 5aa558232edc30468d1f35108826dd5b3ffe978f or 18048cba444a7c41dbf42c180d6b46606fc24c51 or 08272646cd7c310642c39b7f54348fddd7987643 or 0c29e149b6bb498778ed8a1c9597b51acfba7856, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.19.256 or 5.4.211 or 5.10.137 or 5.15.61, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 8cb7cf56c9fe5412de238465b27ef35b4d2801aa up to, but not including, 5aa558232edc30468d1f35108826dd5b3ffe978f; 8cb7cf56c9fe5412de238465b27ef35b4d2801aa up to, but not including, 18048cba444a7c41dbf42c180d6b46606fc24c51; 8cb7cf56c9fe5412de238465b27ef35b4d2801aa up to, but not including, 08272646cd7c310642c39b7f54348fddd7987643; 8cb7cf56c9fe5412de238465b27ef35b4d2801aa up to, but not including, 0c29e149b6bb498778ed8a1c9597b51acfba7856; 8cb7cf56c9fe5412de238465b27ef35b4d2801aa up to, but not including, 87c4896d5dd7fd9927c814cf3c6289f41de3b562; 8cb7cf56c9fe5412de238465b27ef35b4d2801aa up to, but not including, 4f2d7b46d6b53c07f44a4f8f8f4438888f0e9e87; 8cb7cf56c9fe5412de238465b27ef35b4d2801aa up to, but not including, 689640efc0a2c4e07e6f88affe6d42cd40cc3f85; 4.4 | 5aa558232edc30468d1f35108826dd5b3ffe978f, 18048cba444a7c41dbf42c180d6b46606fc24c51, 08272646cd7c310642c39b7f54348fddd7987643, 0c29e149b6bb498778ed8a1c9597b51acfba7856, 87c4896d5dd7fd9927c814cf3c6289f41de3b562, 4f2d7b46d6b53c07f44a4f8f8f4438888f0e9e87 |
| Linux | Linux Kernel | 4.4 up to, but not including, 4.19.256; 4.20 up to, but not including, 5.4.211; 5.5 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 | 4.19.256, 5.4.211, 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 | 7.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: firmware: arm_scpi: Ensure scpi_info is not assigned if the probe fails When scpi probe fails, at any point, we need to ensure that the scpi_info is not set and will remain NULL until the probe succeeds. If it is not taken care, then it could result use-after-free as the value is exported via get_scpi_ops() and could refer to a memory allocated via devm_kzalloc() but freed when the probe fails.
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
- git.kernel.org/stable/c/08272646cd7c310642c39b7f54348fddd7987643
- git.kernel.org/stable/c/0c29e149b6bb498778ed8a1c9597b51acfba7856
- git.kernel.org/stable/c/18048cba444a7c41dbf42c180d6b46606fc24c51
- git.kernel.org/stable/c/4f2d7b46d6b53c07f44a4f8f8f4438888f0e9e87
- git.kernel.org/stable/c/5aa558232edc30468d1f35108826dd5b3ffe978f
- git.kernel.org/stable/c/689640efc0a2c4e07e6f88affe6d42cd40cc3f85
- git.kernel.org/stable/c/87c4896d5dd7fd9927c814cf3c6289f41de3b562
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
Spotted an error? Tell us.