CVE-2021-3493

CVSS v3.1 7.8 (High)

CVSS v2.0 7.2 (High)

EPSS 0.59 % (79^th)

Affected Products 1

Advisories 4

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.

Weaknesses

CWE-270: Privilege Context Switching Error
CWE-863: Incorrect Authorization

CVE Status: PUBLISHED
CNA: Canonical Ltd.
Published Date: 2021-04-17 05:15:14
(3 years ago)
Updated Date: 2023-07-07 19:10:36
(14 months ago)

Linux Kernel Privilege Escalation Vulnerability (CISA - Known Exploited Vulnerabilities Catalog)

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.
Required Action: Apply updates per vendor instructions.
Known to be Used in Ransomware Campaigns: Unknown
Notes: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52; https://nvd.nist.gov/vuln/detail/CVE-2021-3493

Vendor: Linux
Product: Kernel
In CISA Catalog from: 2022-10-20
(23 months ago)
Due Date: 2022-11-10
(22 months ago)

Affected Products

Canonical

Ubuntu Linux

Configuration #1

		CPE23	From	Up To
	Canonical Ubuntu Linux prior 18.04 version	cpe:2.3:o:canonical:ubuntu_linux::::*:lts		< 18.04
	Canonical Ubuntu Linux from 18.04.1 version and prior 20.04 version	cpe:2.3:o:canonical:ubuntu_linux::::*:lts	>= 18.04.1	< 20.04

Configuration #2

		CPE23	From	Up To
	Canonical Ubuntu Linux prior 20.10 version	cpe:2.3:o:canonical:ubuntu_linux::::*:-		< 20.10