CVE-2021-3493
Linux Kernel Privilege Escalation Vulnerability
This vulnerability is in the CISA Known Exploited Vulnerabilities catalog: attackers are using it. If you run Linux, fix it now.
CISA required action: Apply updates per vendor instructions.
US federal civilian agencies must remediate by Nov 10, 2022.
Patch status
Official fix available since
Apply the vendor's update to every affected system. Check the fixed-in versions below where known.
Basis: NVD patch reference
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.
Source: NIST National Vulnerability Database. Official vulnerability data, reproduced as published.
Affected products
| Product | Vendor | Source |
|---|---|---|
| Linux | Linux | KEV |
Sources: KEV = CISA Known Exploited Vulnerabilities catalog. Version details have not been published yet.
Intelligence timeline
Developments from the last 30 days, newest first.
- CVSS scoredUpdateKEV
CVE-2021-3493 scored CVSS 7.8: Linux Kernel, Linux Kernel Privilege Escalation Vulnerability
CISA lists this as exploited in the wild. Unpatched Kernel systems are exposed to active attacks now.
Basis: NIST National Vulnerability Database
- Patch releasedUpdateKEV
Patch released for CVE-2021-3493: Linux Kernel, Linux Kernel Privilege Escalation Vulnerability
An official fix is now available for Linux Kernel. This vulnerability is being exploited, so apply it promptly.
Basis: NVD patch reference
1 earlier event is available with a subscription. See plans.
Coverage
We have not published a story about this vulnerability yet.