Vulnerability Intelligence Report
CVE-2021-3656
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.
No Active Exploit Signals
CVSS Base Score
8.8
HIGH
EPSS Probability:0.66%
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
—
Authentication
—
Weaponization
—
SSVC Action
—
Weaknesses (CWE)
CWE-862 ↗CWE-862
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| linux | linux_kernel | 5.14 |
| fedoraproject | fedora | 33, 34 |
| redhat | software_collections | all |
| redhat | enterprise_linux_server | 7.0 |
| redhat | openstack | 13 |
| redhat | enterprise_linux | 8.0, 7.0 |
| redhat | enterprise_linux_desktop | 7.0 |
| redhat | enterprise_linux_eus | 8.1, 8.2, 8.4 |
| redhat | enterprise_linux_for_ibm_z_systems | 7.0, 8.0 |
| redhat | enterprise_linux_for_ibm_z_systems_eus | 8.1, 8.2, 8.4 |
| redhat | enterprise_linux_for_power_big_endian | 7.0 |
| redhat | enterprise_linux_for_power_little_endian | 7.0, 8.0 |
| redhat | enterprise_linux_for_power_little_endian_eus | 8.1, 8.2, 8.4 |
| redhat | enterprise_linux_for_real_time | 7, 8 |
| redhat | enterprise_linux_for_real_time_for_nfv | 7, 8 |
| redhat | enterprise_linux_for_real_time_for_nfv_tus | 8.2, 8.4 |
| redhat | enterprise_linux_for_real_time_tus | 8.2, 8.4 |
| redhat | enterprise_linux_for_scientific_computing | 7.0 |
| redhat | enterprise_linux_server_aus | 7.6, 7.7, 8.2, 8.4 |
| redhat | enterprise_linux_server_for_power_little_endian_update_services_for_sap_solutions | 7.6, 8.1, 8.2, 8.4 |
| redhat | enterprise_linux_server_tus | 7.6, 7.7, 8.2, 8.4 |
| redhat | enterprise_linux_server_update_services_for_sap_solutions | 7.6, 7.7, 8.1, 8.2, 8.4 |
| redhat | enterprise_linux_workstation | 7.0 |
| redhat | 3scale_api_management | 2.0 |
| redhat | codeready_linux_builder | all |
| redhat | virtualization_host | 4.0 |
Threat Intelligence Signals
EPSS Score
0.658%
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | Red Hat, Inc. · Vendor · USA |
| Reserved | 2021-07-21T00:00:00 |
| Published | 2022-03-04T18:41:26 |
| Last Updated | 2024-08-03T17:01:07 |
Community Chatter & Buzz