overlayfs on Ubuntu privileges management

CVSS Meta Temp Score
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CTI Interest Score
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8.3$0-$5k0.00

Summaryinfo

A vulnerability was found in overlayfs on Ubuntu. It has been classified as critical. This impacts an unknown function. The manipulation leads to privileges management. This vulnerability is documented as CVE-2021-3493. The attack can be initiated remotely. Additionally, an exploit exists. To fix this issue, it is recommended to deploy a patch.

Detailsinfo

A vulnerability, which was classified as critical, has been found in overlayfs on Ubuntu (unknown version). This issue affects an unknown code block. The manipulation with an unknown input leads to a privileges management vulnerability. Using CWE to declare the problem leads to CWE-269. The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor. Impacted is confidentiality, integrity, and availability.

The weakness was released 04/17/2021 as USN-4917-1. It is possible to read the advisory at ubuntu.com. The identification of this vulnerability is CVE-2021-3493. Technical details are unknown but an exploit is available. The attack technique deployed by this issue is T1068 according to MITRE ATT&CK.

It is declared as attacked. The vulnerability scanner Nessus provides a plugin with the ID 276342 (TencentOS Server 2: kernel (TSSA-2024:0557)), which helps to determine the existence of the flaw in a target environment. The CISA Known Exploited Vulnerabilities Catalog lists this issue since 10/20/2022 with a due date of 11/10/2022:

Apply updates per vendor instructions.

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

The vulnerability is also documented in the vulnerability database at Tenable (276342). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.5
VulDB Meta Temp Score: 8.3

VulDB Base Score: 8.8
VulDB Temp Score: 8.4
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔍

CNA Base Score: 8.8
CNA Vector (Canonical Ltd.): 🔍

CVSSv2info

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

NVD Base Score: 🔍

Exploitinginfo

Class: Privileges management
CWE: CWE-269 / CWE-266
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔍
Status: Attacked

EPSS Score: 🔍
EPSS Percentile: 🔍

KEV Added: 🔍
KEV Due: 🔍
KEV Remediation: 🔍
KEV Ransomware: 🔍
KEV Notice: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 276342
Nessus Name: TencentOS Server 2: kernel (TSSA-2024:0557)

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔍

Patch: git.kernel.org

Timelineinfo

04/12/2021 🔍
04/17/2021 +5 days 🔍
04/17/2021 +0 days 🔍
11/23/2025 +1681 days 🔍

Sourcesinfo

Advisory: USN-4917-1
Status: Confirmed

CVE: CVE-2021-3493 (🔍)
GCVE (CVE): GCVE-0-2021-3493
GCVE (VulDB): GCVE-100-173171
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 04/17/2021 16:14
Updated: 11/23/2025 16:59
Changes: 04/17/2021 16:14 (38), 04/23/2021 07:48 (5), 04/23/2021 07:53 (1), 04/28/2021 06:43 (18), 04/27/2024 19:05 (28), 09/26/2024 00:32 (1), 02/19/2025 21:51 (12), 11/23/2025 16:59 (2)
Complete: 🔍
Cache ID: 216::103

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

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