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.
Metrics
Affected Vendors & Products
Advisories
| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-2785-1 | linux-4.19 security update |
Debian DSA |
DSA-4978-1 | linux security update |
EUVD |
EUVD-2021-26951 | 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. |
Ubuntu USN |
USN-5070-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-5071-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-5071-2 | Linux kernel (HWE) vulnerabilities |
Ubuntu USN |
USN-5072-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-5073-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-5073-2 | Linux kernel (GCP) vulnerabilities |
Ubuntu USN |
USN-5082-1 | Linux kernel (OEM) vulnerabilities |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
No history.
Status: PUBLISHED
Assigner: redhat
Published:
Updated: 2024-08-03T17:01:07.792Z
Reserved: 2021-07-21T00:00:00
Link: CVE-2021-3656
No data.
Status : Modified
Published: 2022-03-04T19:15:08.677
Modified: 2024-11-21T06:22:05.187
Link: CVE-2021-3656
OpenCVE Enrichment
No data.
Debian DLA
Debian DSA
EUVD
Ubuntu USN