CVE-2021-3653
8.8 · HIGHOverview
CVE-2021-3653 is a high-severity vulnerability affecting linux linux_kernel. It was published on September 29, 2021 and has a CVSS 3.1 base score of 8.8 (HIGH).
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
A flaw was found in the KVM's AMD code for supporting SVM nested virtualization. The flaw occurs when processing the VMCB (virtual machine control block) provided by the L1 guest to spawn/handle a nested guest (L2). Due to improper validation of the "int_ctl" field, this issue could allow a malicious L1 to enable AVIC support (Advanced Virtual Interrupt Controller) for the L2 guest. As a result, the L2 guest would be allowed to read/write physical pages of the host, resulting in a crash of the entire system, leak of sensitive data or potential guest-to-host escape. This flaw affects Linux kernel versions prior to 5.14-rc7.
Remediation
Check the references section for vendor advisories and patches from linux. Update linux_kernel 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 |
|---|---|---|---|
| linux | linux_kernel | >= 2.6.30, < 4.4.282 | Affected |
References
Frequently Asked Questions
What is CVE-2021-3653?
CVE-2021-3653 is a high-severity vulnerability affecting linux linux_kernel. It was published on September 29, 2021 and has a CVSS 3.1 base score of 8.8 (HIGH).
How severe is CVE-2021-3653?
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-2021-3653?
Check the references section for vendor advisories and patches from linux. Update linux_kernel 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-2021-3653?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-3653 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.
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