PT-2021-6073 · Linux+10 · Linux Kernel+10
Maxim Levitsky
·
Published
2021-08-16
·
Updated
2024-06-15
·
CVE-2021-3653
CVSS v3.1
8.8
High
| Vector | AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |
Name of the Vulnerable Software and Affected Versions
Linux kernel versions prior to 5.14-rc7
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.Recommendations
For Linux kernel versions prior to 5.14-rc7, update to version 5.14-rc7 or later to resolve the issue. As a temporary workaround, consider disabling the nested virtualization feature until a patch is available. Restrict access to the VMCB to minimize the risk of exploitation. Avoid using the
int ctl field in the VMCB until the issue is resolved.Exploit
Fix
Missing Authorization
Found an issue in the description? Have something to add? Feel free to write us 👾
Related Identifiers
Affected Products
Alt Linux
Almalinux
Astra Linux
Centos
Linuxmint
Linux Kernel
Red Hat
Red Os
Rocky Linux
Suse
Ubuntu