Risk Letters
About Sign in ENDA

Exploited vulnerability

CVE-2021-3493

TLP:CLEAR

Linux Kernel Privilege Escalation Vulnerability

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.

Facts

  • Vendor: Linux
  • Product: Kernel
  • CVSS: 8.8
  • EPSS (probability of exploitation within 30 days): 49.2 %
  • On CISA's Known Exploited Vulnerabilities list since: 20 October 2022
  • First known exploitation: 20 October 2022
  • CISA's deadline for US federal agencies: 10 November 2022
  • Weakness: CWE-862
  • First seen by Risk Letters: 20 October 2022

Members see which Nordic sectors the flaw hits, and what to do about it.

Get the full brief

Data: NVD (public domain), CISA KEV, FIRST EPSS, MITRE ATT&CK, AlienVault OTX. NVD

© The Risk Letters 2026 · Privacy policy · Terms of sale · Refund policy