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PatchSiren cyber security CVE debrief

CVE-2026-89930 Linux CVE debrief

A critical vulnerability in the Linux kernel's KVM (Kernel-based Virtual Machine) component has been identified, affecting the handling of nested VM-Enter operations. This issue could potentially allow attackers to exploit the system, although the specifics of such exploitation are not detailed in the provided sources. The vulnerability is related to the KVM: nVMX component, specifically with servicing local TLB flushes on failed nested VM-Enter operations. Linux system administrators and security teams should assess exposure, apply patches, and monitor systems for potential security issues. The CVE record was published on 2026-09-16T10:32:21.535Z and has not been modified since. K

Vendor
Linux
Product
Unknown
CVSS
CRITICAL 9.3
CISA KEV
Not listed in stored evidence
Original CVE published
2026-09-16
Original CVE updated
2026-10-19
Advisory published
2026-09-16
Advisory updated
2026-10-19

Who should care

Linux system administrators, virtualization engineers, and security teams responsible for Linux-based infrastructure should assess exposure and apply patches or mitigations as necessary.

Why it matters

CVE-2026-89930 is a critical vulnerability in the Linux kernel's KVM component affecting nested VM-Enter operations. Linux system administrators and security teams should assess exposure, apply patches, and monitor systems for potential security issues.

  • Verify Linux kernel versions and KVM configurations for exposure
  • Apply patches or updates from Linux vendors to address the vulnerability
  • Monitor system logs for potential exploitation attempts
  • Review virtualization configurations for secure deployment

Technical summary

The Linux kernel's KVM component is vulnerable due to improper handling of local TLB flushes during failed nested VM-Enter operations. This could lead to potential security issues if exploited. Several Linux kernel commits are referenced as part of the fix, including c0c66cd575e31218da6a7d104c6ef80b0830b60c and 1025b938dc439b75c720a568a855a13eeb245686. The vulnerability is related to the KVM: nVMX component, specifically with servicing local TLB flushes on failed nested VM-Enter operations. Linux system administrators and security teams should assess exposure, apply patches, and monitor systems for potential security issues.

Defensive priority

High

Recommended defensive actions

  • Review and apply patches from Linux vendors for KVM: nVMX local TLB flush handling
  • Monitor Linux kernel updates for fixes related to nested VM-Enter operations
  • Assess exposure of Linux-based systems using KVM for virtualization
  • Verify Linux kernel versions and KVM configurations for exposure
  • Apply patches or updates from Linux vendors to address the vulnerability
  • Monitor system logs for potential exploitation attempts
  • Review virtualization configurations for secure deployment

Evidence notes

The vulnerability is related to the KVM: nVMX component, specifically with servicing local TLB flushes on failed nested VM-Enter operations. The Linux kernel's KVM component is impacted, and several references to specific commits and code changes are provided.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-89930 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-89930

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-89930 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-89930

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • KVM: nVMX: Service local TLB flushes on failed nested VM-Enter

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/89xxx/CVE-2026-89930.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/c0c66cd575e31218da6a7d104c6ef80b0830b60c

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/1025b938dc439b75c720a568a855a13eeb245686

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/312cdb6d8940827dea63a7a52fb714a5049f06d1

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/f74fccdf4f7fb0780cd84944108d35f3d9dc46a7

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/c43563e7518e65ec6ccaa6a65f84c5af5ca5d379

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/62c3ee4c9f0e2efef5157358b3549e50ede96d73

    Supplemental source

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/05a0b701d1089fb57beeb8982f23c3bbafe0fa8b

    Supplemental source

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.