CVE-2021-3732

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ModerateModerate ImpactWhat does this mean?

3.3CVSS v3 Score Breakdown

Description

Mitigation

Additional information

CVSS Score Details

Weakness (CWE)

Acknowledgements

FAQ

Description

A flaw was found in the Linux kernel’s OverlayFS subsystem in the way the user mounts the TmpFS filesystem with OverlayFS. This flaw allows a local user to gain access to hidden files that should not be accessible.

Mitigation

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Additional information

Bugzilla 1995249: kernel: overlayfs: Mounting overlayfs inside an unprivileged user namespace can reveal files
CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
FAQ: Frequently asked questions about CVE-2021-3732

External references

https://www.cve.org/CVERecord?id=CVE-2021-3732

https://nvd.nist.gov/vuln/detail/CVE-2021-3732

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=427215d85e8d

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	3.3	5.5
Attack Vector	Local	Local
Attack Complexity	Low	Low
Privileges Required	Low	Low
User Interaction	None	None
Scope	Unchanged	Unchanged
Confidentiality Impact	Low	High
Integrity Impact	None	None
Availability Impact	None	None

CVSS v3 Vector

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

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

Acknowledgements

This issue was discovered by Miklos Szeredi (Red Hat).

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?

"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.
The term "Affected" means that our Analysis team has determined that this product, such as Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to address this issue in the near future. This includes all minor releases of this product unless noted otherwise in the Statement text.

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.

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CVE-2021-3732

Description

Mitigation

Additional information

External references

Common Vulnerability Scoring System (CVSS) Score Details

Important note

CVSS v3 Vector

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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