DEBIAN-CVE-2021-3656

Advisory lineage Upstream: 1 Downstream: 2
Upstream
CVE-2021-3656
Published: 04 Mar 2022, 19:15
Last modified:28 Apr 2026, 20:22

Vulnerability Summary

Overall Risk (default)
medium
35/100
CVSS Score
8.8 HIGH
3.1 (osv_debian)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

04 Mar 2022, 19:15
Published
Vulnerability first disclosed
28 Apr 2026, 20:22
Last Modified
Vulnerability information updated

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 "virt_ext" field, this issue could allow a malicious L1 to disable both VMLOAD/VMSAVE intercepts and VLS (Virtual VMLOAD/VMSAVE) 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.

CVSS Metrics

  • v3.1•HIGH•Score: 8.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Affected Systems

  • debian•linux

    < 5.10.46-5 | < 5.14.6-1 | < 5.14.6-1 | < 5.14.6-1

References (1)