VULNERABILITY INTELLIGENCE
CVE-2021-3493
CVSS score8.8 HIGH
EPSS probability49.17%
CISA KEVKnown exploited vulnerability
Published2021-04-17
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Known Exploited Vulnerability
Linux Kernel Privilege Escalation Vulnerability
Vendor / product: Linux / Kernel
Description
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.
Weakness classification
- security@ubuntu.com: CWE-270
- nvd@nist.gov: CWE-863
Primary references
- security@ubuntu.com — Exploit, Third Party Advisory, VDB Entry
- security@ubuntu.com — Press/Media Coverage, Third Party Advisory, VDB Entry
- security@ubuntu.com — Exploit, Third Party Advisory, VDB Entry
- security@ubuntu.com — Mailing List, Patch, Third Party Advisory
- security@ubuntu.com — Vendor Advisory
- security@ubuntu.com — Mailing List, Third Party Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Exploit, Third Party Advisory, VDB Entry
- af854a3a-2127-422b-91ae-364da2661108 — Press/Media Coverage, Third Party Advisory, VDB Entry
- af854a3a-2127-422b-91ae-364da2661108 — Exploit, Third Party Advisory, VDB Entry
- af854a3a-2127-422b-91ae-364da2661108 — Mailing List, Patch, Third Party Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Vendor Advisory
- af854a3a-2127-422b-91ae-364da2661108 — Mailing List, Third Party Advisory