CVE-2021-3493
8.8 · HIGH Actively ExploitedOverview
CVE-2021-3493 is a high-severity vulnerability affecting canonical ubuntu_linux. It was published on April 17, 2021 and has a CVSS 3.1 base score of 8.8 (HIGH). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.
This vulnerability has a CVSS 3.1 base score of 8.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical 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.
Remediation
Check the references section for vendor advisories and patches from canonical. Update ubuntu_linux to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| canonical | ubuntu_linux | >= 0, < 18.04 | Affected |
References
Frequently Asked Questions
What is CVE-2021-3493?
CVE-2021-3493 is a high-severity vulnerability affecting canonical ubuntu_linux. It was published on April 17, 2021 and has a CVSS 3.1 base score of 8.8 (HIGH). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.
How severe is CVE-2021-3493?
This vulnerability has a CVSS 3.1 base score of 8.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2021-3493?
Check the references section for vendor advisories and patches from canonical. Update ubuntu_linux to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-3493?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-3493 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
AI-driven PR review catches vulnerable dependencies before they ship.
Browser-based exploitation validates findings with real proof-of-concept.
Related HIGH CVEs from 2021
View all →systeminformation is an open source system and OS information library for node.js. A command injecti
An Improper Access Control Privilege Escalation Vulnerability was discovered in the User Setting of
An SQL injection Privilege Escalation Vulnerability was discovered in the Orion Platform reported by
Insecure deserialization leading to Remote Code Execution was detected in the Orion Platform version
Insecure Deserialization of untrusted data remote code execution vulnerability was discovered in Pat
Deserialization of Untrusted Data in the Web Console Chart Endpoint can lead to remote code executio
Insecure Deseralization of untrusted data remote code execution vulnerability was discovered in Patc
SAP Web Dispatcher versions - 7.49, 7.53, 7.77, 7.81, KRNL64NUC - 7.22, 7.22EXT, 7.49, KRNL64UC -7.2
uploader.php in the KCFinder integration project through 2018-06-01 for Drupal mishandles validation
An issue was discovered in the PageLayer plugin before 1.1.2 for WordPress. The pagelayer_settings_p
MK-AUTH through 19.01 K4.9 allows CSRF for password changes via the central/executar_central.php?aca
IBM Cloud Pak System 2.3 is vulnerable to cross-site request forgery which could allow an attacker t