CVE-2022-0185

Known exploitThis CVE is high risk and there are known public exploits leveraging this vulnerability. Address this vulnerability with high priority.

Public on

Last Modified: UTC

ImportantImportant ImpactWhat does this mean?

7.8CVSS v3 Score Breakdown

Description

Statement

Mitigation

Additional information

CVSS Score Details

Weakness (CWE)

Acknowledgements

FAQ

Description

A heap-based buffer overflow flaw was found in the way the legacy_parse_param function in the Filesystem Context functionality of the Linux kernel verified the supplied parameters length. An unprivileged (in case of unprivileged user namespaces enabled, otherwise needs namespaced CAP_SYS_ADMIN privilege) local user able to open a filesystem that does not support the Filesystem Context API (and thus fallbacks to legacy handling) could use this flaw to escalate their privileges on the system.

Statement

This issue affects the Linux kernel packages as shipped with Red Hat Enterprise Linux 8.4 GA onwards. Previous Red Hat Enterprise Linux versions are not affected.

Mitigation

On non-containerized deployments of Red Hat Enterprise Linux 8, you can disable user namespaces by setting user.max_user_namespaces to 0:

# echo "user.max_user_namespaces=0" > /etc/sysctl.d/userns.conf
# sysctl -p /etc/sysctl.d/userns.conf

On containerized deployments, such as Red Hat OpenShift Container Platform, do not use this mitigation as the functionality is needed to be enabled.

Additional information

Bugzilla 2040358: kernel: fs_context: heap overflow in legacy parameter handling
CWE-191: Integer Underflow (Wrap or Wraparound)
FAQ: Frequently asked questions about CVE-2022-0185

External references

https://www.cve.org/CVERecord?id=CVE-2022-0185

https://nvd.nist.gov/vuln/detail/CVE-2022-0185

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=722d94847de2

https://github.com/Crusaders-of-Rust/CVE-2022-0185

https://www.openwall.com/lists/oss-security/2022/01/18/7

https://www.willsroot.io/2022/01/cve-2022-0185.html

https://www.cisa.gov/known-exploited-vulnerabilities-catalog

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 Authority (CNA) source for its products and services (see Red Hat classifications).

CVSS v3 Score Breakdown
	Red Hat	NVD
CVSS v3 Base Score	7.8	8.4
Attack Vector	Local	Local
Attack Complexity	Low	Low
Privileges Required	Low	None
User Interaction	None	None
Scope	Unchanged	Unchanged
Confidentiality Impact	High	High
Integrity Impact	High	High
Availability Impact	High	High

CVSS v3 Vector

Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

NVD: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Understanding the Weakness (CWE)

CWE-191

Availability

Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Instability

This weakness will generally lead to undefined behavior and therefore crashes. In the case of overflows involving loop index variables, the likelihood of infinite loops is also high.

Integrity

Technical Impact: Modify Memory

If the value in question is important to data (as opposed to flow), simple data corruption has occurred. Also, if the wrap around results in other conditions such as buffer overflows, further memory corruption may occur.

Confidentiality,Availability,Access Control

Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism

This weakness can sometimes trigger buffer overflows which can be used to execute arbitrary code. This is usually outside the scope of a program's implicit security policy.

Acknowledgements

Red Hat would like to thank Alec Petridis (alecthechop@gmail.com), Hrvoje Mišetić (misetichrvoje@gmail.com), Isaac Badipe (isaac.badipe@gmail.com), Jamie Hill-Daniel (jamie@hill-daniel.co.uk), Philip Papurt (g@gnk.io), and William Liu (willsroot@protonmail.com) for reporting this issue.

Frequently Asked Questions

Why is Red Hat's CVSS v3 score or Impact different from other vendors?

For open source software shipped by multiple vendors, the CVSS base scores may vary for each vendor's version depending on the version they ship, how they ship it, the platform, and even how the software is compiled. This makes scoring of vulnerabilities difficult for third-party vulnerability databases such as NVD that only provide a single CVSS base score for each vulnerability. Red Hat scores reflect how a vulnerability affects our products specifically.

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?

What can I do if my product is listed as "Will not fix"?

A "will not fix" status means that a fix for an affected product version is not planned or not possible due to complexity, which may create additional risk.

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 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"?

A deferred status means that a fix for an affected product version is not guaranteed due to higher-priority development work.

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 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?

In order to maintain code stability and compatibility, Red Hat usually does not rebase packages to entirely new versions. Instead, we backport fixes and new features to an older version of the package we distribute. This can result in some security scanners that only consider the package version to report the package as vulnerable. To avoid this, we suggest that you use an approved vulnerability scanner from our Red Hat Vulnerability Scanner Certification program.

Not sure what something means? Check out our Security Glossary.

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CVE-2022-0185

Description

Statement

Mitigation

Additional information

External references

Common Vulnerability Scoring System (CVSS) Score Details

Important note

CVSS v3 Vector

Understanding the Weakness (CWE)

Availability

Integrity

Confidentiality,Availability,Access Control

Acknowledgements

Frequently Asked Questions

Why is Red Hat's CVSS v3 score or Impact different from other vendors?

My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?

What can I do if my product is listed as "Will not fix"?

What can I do if my product is listed as "Fix deferred"?

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?

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