CVE-2022-50473
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Description
An initialization order bug was found in the Linux kernel's cpufreq subsystem during policy allocation. A local user can trigger this issue when CPU frequency policy initialization fails after kobject registration but before completion initialization, causing the cleanup path to attempt to use an uninitialized completion variable. This results in a page fault and kernel crash, leading to denial of service.
Statement
The cpufreq_policy_alloc function creates CPU frequency policy objects and registers them with the sysfs kobject infrastructure. During this process, a completion variable is used for synchronization when the policy object is eventually released. The problem is timing: kobject_init_and_add can fail, triggering an error cleanup path that calls kobject_put. This leads to cpufreq_sysfs_release being invoked, which tries to complete on the completion variable—but that variable hasn't been initialized yet because init_completion is called after the kobject registration. Accessing an uninitialized completion causes the kernel to dereference invalid memory (specifically address 0xfffffffffffffff8), resulting in an immediate page fault and crash. This can happen during normal CPU frequency driver initialization when any of various failure conditions occur, such as memory allocation failures or sysfs registration conflicts.
Additional Information
- This content is not included.Bugzilla 2401530: kernel: cpufreq: Init completion before kobject_init_and_add()
- Content from cwe.mitre.org is not included.CWE-909: Missing Initialization of Resource
- FAQ: Frequently asked questions about CVE-2022-50473
- Offline Security Data data is available for integration with other systems. See Offline Security Data API to get started.
External References
Content from www.cve.org is not included.https://www.cve.org/CVERecord?id=CVE-2022-50473
Content from nvd.nist.gov is not included.https://nvd.nist.gov/vuln/detail/CVE-2022-50473
Affected Packages and Issued Red Hat Security Errata
| Products / Services | Components | State | Errata |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Not affected | |
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | |
| Red Hat Enterprise Linux 7 | kernel | Not affected | |
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | |
| Red Hat Enterprise Linux 8 | kernel-rt | Fix deferred | |
| Red Hat Enterprise Linux 8 | kernel | Fixed | RHSA-2020:1769 |
| Red Hat Enterprise Linux 8 | kernel | Fixed | RHSA-2023:7077 |
| Red Hat Enterprise Linux 9 | kernel-rt | Fix deferred | |
| Red Hat Enterprise Linux 9 | kernel | Fixed | RHSA-2023:6583 |
Common Vulnerability Scoring System (CVSS) Score Details
Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authorities (CNA) source for its products and services (see Red Hat classifications ).
| CVSS v3 Score Breakdown | Red Hat | NVD |
|---|---|---|
| CVSS v3 Base Score | 5.5 | 5.5 |
| Attack Vector | Local | Local |
| Attack Complexity | Low | Low |
| Privileges Required | Low | Low |
| User Interaction | None | None |
| Scope | Unchanged | Unchanged |
| Confidentiality Impact | None | None |
| Integrity Impact | None | None |
| Availability Impact | High | High |
CVSS v3 Vector
Red Hat CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Frequently Asked Questions
Why is Red Hat's CVSS v3 score or Impact different from other vendors?
For more information, see https://access.redhat.com/solutions/762393.
My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
- "Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.
- "Affected" means that our Analysis Team has determined that this product is affected by this vulnerability and might release a fix to address this in the near future.
What can I do if my product is listed as "Will not fix"?
Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
- Upgrade to a supported product version that includes a fix for this vulnerability (recommended).
- Apply a mitigation (if one exists).
- Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.
What can I do if my product is listed as "Fix deferred"?
Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
- Apply a mitigation (if one exists).
- Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.
- Red Hat Engineering focuses on addressing high-priority issues based on their complexity or limited lifecycle support. Therefore, lower-priority issues will not receive immediate fixes.
What is a mitigation?
I have a Red Hat product but it is not in the above list, is it affected?
Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?
My product is listed as "Out of Support Scope". What does this mean?
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