CVE-2022-27672

Description

A flaw was found in HW. When SMT is enabled, certain AMD processors may speculatively execute instructions using a target from the sibling thread after an SMT mode switch, potentially resulting in information disclosure.

Statement

The Red Hat Enterprise Linux 8 and 9 are not affected if spectre_v2 mitigation enabled (and it is enabled by default).

Mitigation

The current mitigations for spectre V4 (or spectre_v2) should mitigate this flaw, no additional steps will need to be taken.

In more details, according to the article
https://kernel.org/doc/html//next/admin-guide/hw-vuln/cross-thread-rsb.html

Two mitigations are needed:

1) Stuff the RSB during context switch which is already being done in RHEL8/RHEL9 as long as the spectre_v2 mitigation is active.
2) For KVM, the mitigation for the KVM_CAP_X86_DISABLE_EXITS capability can be turned on using the boolean module parameter mitigate_smt_rsb, e.g. vm.mitigate_smt_rsb=1.

The command to check if mitigation is active:
cat /sys/devices/system/cpu/vulnerabilities/spectre_v2

Common Vulnerability Scoring System (CVSS) Score Details

Info alert:Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).

CVSS v3 Score Breakdown

Red HatNVDcve.org
Base Score4.74.7N/A
Attack VectorLocalLocalN/A
Attack ComplexityHighHighN/A
Privileges RequiredLowLowN/A
User InteractionNoneNoneN/A
ScopeUnchangedUnchangedN/A
ConfidentialityHighHighN/A
Integrity ImpactNoneNoneN/A
Availability ImpactNoneNoneN/A

Vector

Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

NVD: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

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