The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges.
CVE-2021-3493 - High Severity Vulnerability
The Linux Kernel
Library home page: https://mirrors.edge.kernel.org/pub/linux/kernel/v4.x/?wsslib=linux
Found in HEAD commit: ed48650604b1d1d694b8e4b96732faa74080f35a
Found in base branch: master
The overlayfs implementation in the linux kernel did not properly validate with respect to user namespaces the setting of file capabilities on files in an underlying file system. Due to the combination of unprivileged user namespaces along with a patch carried in the Ubuntu kernel to allow unprivileged overlay mounts, an attacker could use this to gain elevated privileges.
Publish Date: 2021-04-17
URL: CVE-2021-3493
Base Score Metrics: - Exploitability Metrics: - Attack Vector: Local - Attack Complexity: Low - Privileges Required: Low - User Interaction: None - Scope: Changed - Impact Metrics: - Confidentiality Impact: High - Integrity Impact: High - Availability Impact: High
For more information on CVSS3 Scores, click here.Type: Upgrade version
Origin: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3493
Release Date: 2021-04-17
Fix Resolution: v5.11-rc1
Step up your Open Source Security Game with Mend here