CVE-2023-53208

Host denial of service via flawed TSC assertion

Published Sep 15, 2025 · Updated Sep 15, 2025

Denial of service in Linux kernel KVM 5.16 through 6.1.53 and 6.2 through 6.5.3 allows local users to interrupt the host via nSVM. During nested VM-Exit, nested_svm_vmexit tests L2's TSC ratio instead of L1's desired ratio and then asserts that TSC scaling is exposed to L1. Access to KVM and control of guest MSR and CPUID state are required; a crafted mismatch produces an unbounded stream of kernel warnings.

CVSS severity5.5
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Linux kernel KVM 5.16 through 6.1.53 and 6.2 through 6.5.3 allows local users to interrupt the host via nSVM. During nested VM-Exit, nested_svm_vmexit tests L2's TSC ratio instead of L1's desired ratio and then asserts that TSC scaling is exposed to L1. Access to KVM and control of guest MSR and CPUID state are required; a crafted mismatch produces an unbounded stream of kernel warnings.

The record

CVE
CVE-2023-53208
Published
Sep 15, 2025
Updated
Sep 15, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 15, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 15, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.16
  2. Affected versionversion=5228eb96a4875f8cf5d61d486e3795ac14df8904 <0c94e2468491cbf0754f49a5136ab51294a96b69
  3. Affected versionversion=5228eb96a4875f8cf5d61d486e3795ac14df8904 <5b2b0535fa7adee7e295fed0a3095082131a8d05
  4. Affected versionversion=5228eb96a4875f8cf5d61d486e3795ac14df8904 <e91c07f6cf7060d2acb3aeee31a6baebe3773d3f

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.16; version=5228eb96a4875f8cf5d61d486e3795ac14df8904 <0c94e2468491cbf0754f49a5136ab51294a96b69; version=5228eb96a4875f8cf5d61d486e3795ac14df8904 <5b2b0535fa7adee7e295fed0a3095082131a8d05; version=5228eb96a4875f8cf5d61d486e3795ac14df8904 <e91c07f6cf7060d2acb3aeee31a6baebe3773d3f

Published CVSS scores

5.5CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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