CVE-2021-3493: Linux Kernel Privilege Escalation Vulnerability
High · CVSS 8.8 (CVSS 3.1)KEV known exploitedEPSS 49.2%, 99th percentilePublished Updated Assigner: canonical
In CISA’s Known Exploited Vulnerabilities catalog: Linux Kernel Privilege Escalation Vulnerability.
Added , federal remediation due . Known ransomware use: Unknown.
Required action: Apply updates per vendor instructions.
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.
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H · CWE-270
Status incidents that name it
No tracked status incident names this CVE.
Affected vendors and products
Ubuntu: linux kernel
References
- CVE record on cve.org (opens in new tab)
- NVD entry (opens in new tab)
- packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html (opens in new tab)
- packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html (opens in new tab)
- packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html (opens in new tab)
- git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/ (opens in new tab)
- ubuntu.com/security/notices/USN-4917-1 (opens in new tab)
- www.openwall.com/lists/oss-security/2021/04/16/1 (opens in new tab)
- CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (opens in new tab)
- This product uses data from the NVD API but is not endorsed or certified by the NVD. (opens in new tab)
- Known Exploited Vulnerabilities catalog from CISA. (opens in new tab)
- EPSS scores from FIRST (Exploit Prediction Scoring System). (opens in new tab)