Access Restriction Bypass Affecting torvalds/linux package, versions [2.6.30,5.14)


Severity

Recommended
0.0
high
0
10

CVSS assessment made by Snyk's Security Team. Learn more

Threat Intelligence

EPSS
0.01% (2nd percentile)

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  • Snyk IDSNYK-UNMANAGED-TORVALDSLINUX-3006704
  • published26 Jan 2022
  • disclosed29 Sept 2021
  • creditUnknown

Introduced: 29 Sep 2021

CVE-2021-3653  (opens in a new tab)
CWE-862  (opens in a new tab)

How to fix?

Upgrade torvalds/linux to version 5.14 or higher.

Overview

Affected versions of this package are vulnerable to Access Restriction Bypass. 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. This flaw affects Linux kernel versions prior to 5.14-rc7.

CVSS Base Scores

version 3.1