CVE-2021-3493

🗓️ 17 Apr 2021 04:20:16Reported by canonicalType

cve🔗 web.nvd.nist.gov📰️ 11 Media mentions👁 1430 Views

The overlayfs implementation in the linux kernel did not properly validate file capabilities, leading to elevated privileges

Reporter	Title	Published	Views	Family All 72
GithubExploit	lpe-toolkit	21 May 202619:33	–	githubexploit
GithubExploit	Exploit for Privilege Context Switching Error in Canonical Ubuntu_Linux	20 Apr 202609:31	–	githubexploit
GithubExploit	Exploit for Privilege Context Switching Error in Canonical Ubuntu_Linux	25 Feb 202610:30	–	githubexploit
GithubExploit	Exploit for Privilege Context Switching Error in Canonical Ubuntu_Linux	13 Sep 202518:09	–	githubexploit
GithubExploit	Exploit for Privilege Context Switching Error in Canonical Ubuntu_Linux	19 Apr 202120:07	–	githubexploit
GithubExploit	Exploit for Privilege Context Switching Error in Canonical Ubuntu_Linux	2 May 202101:58	–	githubexploit
GithubExploit	Exploit for Privilege Context Switching Error in Canonical Ubuntu_Linux	29 Nov 202212:56	–	githubexploit
GithubExploit	Exploit for Privilege Context Switching Error in Canonical Ubuntu_Linux	25 Feb 202610:30	–	githubexploit
GithubExploit	Exploit for Privilege Context Switching Error in Canonical Ubuntu_Linux	2 Oct 202114:44	–	githubexploit
GithubExploit	Exploit for Privilege Context Switching Error in Canonical Ubuntu_Linux	4 Jul 202417:29	–	githubexploit

NVD

Node

canonical ubuntu_linuxRange<18.04lts

canonical ubuntu_linuxRange18.04.1–20.04lts

Node

canonical ubuntu_linuxRange<20.10-

[
  {
    "product": "linux kernel",
    "vendor": "Ubuntu",
    "versions": [
      {
        "lessThan": "5.8.0-50.56",
        "status": "affected",
        "version": "5.8 kernel",
        "versionType": "custom"
      },
      {
        "lessThan": "5.4.0-72.80",
        "status": "affected",
        "version": "5.4 kernel",
        "versionType": "custom"
      },
      {
        "lessThan": "4.15.0-142.146",
        "status": "affected",
        "version": "4.15 kernel",
        "versionType": "custom"
      },
      {
        "lessThan": "4.4.0-209.241",
        "status": "affected",
        "version": "4.4 kernel",
        "versionType": "custom"
      }
    ]
  }
]

Source	Link
openwall	www.openwall.com/lists/oss-security/2021/04/16/1
ubuntu	www.ubuntu.com/security/notices/USN-4917-1
packetstormsecurity	www.packetstormsecurity.com/files/162866/Ubuntu-OverlayFS-Local-Privilege-Escalation.html
packetstormsecurity	www.packetstormsecurity.com/files/162434/Kernel-Live-Patch-Security-Notice-LSN-0076-1.html
packetstormsecurity	www.packetstormsecurity.com/files/165151/Ubuntu-Overlayfs-Local-Privilege-Escalation.html
git	www.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/
cisa	www.cisa.gov/known-exploited-vulnerabilities-catalog

28 Oct 2025 13:49Current

7.5High risk

Vulners AI Score7.5

CVSS 27.2

CVSS 3.17.8 - 8.8

EPSS0.79706

SSVC

cve-2021-3493 linux kernel overlayfs file capabilities user namespaces ubuntu patch unprivileged mounts security vulnerability