Is CVE-2021-3493 actively exploited?

Yes. CVE-2021-3493 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, which means exploitation in the wild has been confirmed.

Can CVE-2021-3493 be exploited remotely?

The attack vector of CVE-2021-3493 has not been classified yet.

What is the CVSS score of CVE-2021-3493?

CVE-2021-3493 has not received a CVSS score yet.

HOME VULNERABILITIESCVE-2021-3493

HIGHCISA KEVIN THE WILD

CVE-2021-3493

Published: October 20, 2022

EPSS:76.77%probability of exploitation in 30 daysPercentile:98.9th

Official Description

The overlayfs stacking file system in Linux kernel does not properly validate the application of file capabilities against user namespaces, which could lead to privilege escalation.

NVD Source

CISA KEV Advisory

Linux Kernel Privilege Escalation Vulnerability

The overlayfs stacking file system in Linux kernel does not properly validate the application of file capabilities against user namespaces, which could lead to privilege escalation.

Added to KEV: 2022-10-20Federal patch deadline: 2022-11-10

Required Action (CISA)

Apply updates per vendor instructions.

Risk Analysis

The Linux kernel's overlayfs file system has a flaw in validating file capabilities against user namespaces, which can lead to privilege escalation. This is a high-severity vulnerability with an EPSS score of 0.76767, indicating a high likelihood of exploitation, and it is confirmed to be exploited in the wild.

This vulnerability is actively exploited in the wild and is listed in CISA's Known Exploited Vulnerabilities Catalog. Exploitation requires local access to the system to achieve privilege escalation.

Recommended Action

System administrators should update their Linux kernels to a version that addresses the overlayfs vulnerability. Ensure that user namespaces are properly configured and restricted where possible.

Generated by the CTIWATCH analysis pipeline from this CVE's metadata (CVSS, EPSS, KEV status, exploit intelligence). Verify against vendor advisories before acting.

Technical Analysis

CVE-2021-3493 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

CISA has added CVE-2021-3493 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.