Missing Authorization Affecting perf package, versions <0:4.18.0-193.68.1.el8_2


Severity

Recommended
medium

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.04% (5th percentile)

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  • Snyk IDSNYK-RHEL8-PERF-3971532
  • published17 Aug 2021
  • disclosed16 Aug 2021

Introduced: 16 Aug 2021

CVE-2021-3656  (opens in a new tab)
CWE-862  (opens in a new tab)

How to fix?

Upgrade RHEL:8 perf to version 0:4.18.0-193.68.1.el8_2 or higher.
This issue was patched in RHSA-2021:3904.

NVD Description

Note: Versions mentioned in the description apply only to the upstream perf package and not the perf package as distributed by RHEL. See How to fix? for RHEL:8 relevant fixed versions and status.

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 Scores

version 3.1