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CVE-2021-3656

Published: Mar 4, 2022Updated: Nov 21, 2024 Sources: CVE List NVD BDUCWE-862
NVD MITRE
8.8CVSSHIGH
EPSS Score
0.7%
Top 53.4%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

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 Vector Breakdown

AV:LAC:LPR:LUI:NS:CC:HI:HA:H
Exploitability
AV:LAttack Vector
Local
AC:LAttack Complexity
Low
PR:LPrivileges Required
Low
UI:NUser Interaction
None
Scope
S:CScope
Changed
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:HAvailability
High
Open in CVSS calculator →

Weaknesses

CWE-862

Affected Products

KVMn/a
linux kernellinux
On-premOS
Operating Systems
fedorafedoraproject
On-premOS
Operating Systems / linux-distro
software collectionsredhat
On-prem
DevTools & CI / build-test-tools
openstackredhat
On-prem
Cloud & SaaS / container-orchestration
linuxoss-projectOperating Systemsaka the linux kernel
fedoraprojectoss-projectUSOperating Systemsaka fedora project
redhatcommercialUSOperating Systemsaka red hat
and 33 more affected products View all →

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

Exploitability

Official Patch Available

MITRE ATT&CK

2 techniques
Initial Access
View detailed technique mapping

References

https://www.openwall.com/lists/oss-security/2021/08/16/1
openwall.com
https://git.kernel.org/pub/scm/virt/kvm/kvm.git/commit/?id=c7dfa4009965a9b2d7b329ee970eb8da0d32f0bc
git.kernel.org
https://github.com/torvalds/linux/commit/c7dfa4009965a9b2d7b329ee970eb8da0d32f0bc
github.com
and 34 more references View all →

Timeline

Published
Mar 4, 2022
Last Updated
Nov 21, 2024

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