Time-of-check Time-of-use (TOCTOU) Affecting kernel-rt-debug-kvm package, versions <0:4.18.0-513.5.1.rt7.307.el8_9


Severity

Recommended
high

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.04% (11th percentile)

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  • Snyk IDSNYK-RHEL8-KERNELRTDEBUGKVM-5822395
  • published7 Aug 2023
  • disclosed4 Aug 2023

Introduced: 4 Aug 2023

CVE-2023-4155  (opens in a new tab)
CWE-367  (opens in a new tab)

How to fix?

Upgrade RHEL:8 kernel-rt-debug-kvm to version 0:4.18.0-513.5.1.rt7.307.el8_9 or higher.
This issue was patched in RHSA-2023:6901.

NVD Description

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

A flaw was found in KVM AMD Secure Encrypted Virtualization (SEV) in the Linux kernel. A KVM guest using SEV-ES or SEV-SNP with multiple vCPUs can trigger a double fetch race condition vulnerability and invoke the VMGEXIT handler recursively. If an attacker manages to call the handler multiple times, they can trigger a stack overflow and cause a denial of service or potentially guest-to-host escape in kernel configurations without stack guard pages (CONFIG_VMAP_STACK).

CVSS Scores

version 3.1