Linux Kernel OverlayFS Subsystem race condition

CVSS Meta Temp Score
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CTI Interest Score
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5.1$0-$5k0.00

Summaryinfo

A vulnerability classified as problematic has been found in Linux Kernel. This vulnerability affects unknown code of the component OverlayFS Subsystem. This manipulation causes race condition. The identification of this vulnerability is CVE-2021-20321. It is possible to initiate the attack remotely. There is no exploit available. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability classified as problematic was found in Linux Kernel (Operating System) (version now known). Affected by this vulnerability is some unknown processing of the component OverlayFS Subsystem. The manipulation with an unknown input leads to a race condition vulnerability. The CWE definition for the vulnerability is CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. As an impact it is known to affect availability.

The weakness was shared 02/18/2022. It is possible to read the advisory at bugzilla.redhat.com. This vulnerability is known as CVE-2021-20321 since 12/17/2020. The technical details are unknown and an exploit is not publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 235794 (Amazon Linux 2 : kernel (ALASKERNEL-5.4-2025-099)), which helps to determine the existence of the flaw in a target environment.

Applying a patch is able to eliminate this problem. The bugfix is ready for download at lore.kernel.org.

The vulnerability is also documented in the vulnerability database at Tenable (235794). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

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Vendor

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.1

VulDB Base Score: 5.3
VulDB Temp Score: 5.1
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Race condition
CWE: CWE-362
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 235794
Nessus Name: Amazon Linux 2 : kernel (ALASKERNEL-5.4-2025-099)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔍

Patch: lore.kernel.org

Timelineinfo

12/17/2020 🔍
02/18/2022 +428 days 🔍
02/18/2022 +0 days 🔍
05/13/2025 +1180 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: bugzilla.redhat.com
Status: Confirmed

CVE: CVE-2021-20321 (🔍)
GCVE (CVE): GCVE-0-2021-20321
GCVE (VulDB): GCVE-100-193339

Entryinfo

Created: 02/18/2022 20:29
Updated: 05/13/2025 19:11
Changes: 02/18/2022 20:29 (38), 05/13/2025 19:11 (16)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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