VulnSocial

CVE-2026-63940Patch

LOWCVSS 9.3 · CRITICAL

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Patch affected systems immediately

Recommended action window: Monitor and triage in normal cycle

NVD description

In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Ignore Port I/O requests of length '0' Explicitly ignore Port I/O requests of length '0' (or count '0'), so that setting up the software scratch area (and other code) doesn't have to worry about underflowing the length, and to allow for WARNing on trying to configure the scratch area with len==0.

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0.5/ 10 priority

Sources & remediation

Other references
Weakness type (CWE)
CWE-190

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

AVAILABLE

Momentum

STABLE

Threat summary

  • Patch or workaround signal is available
  • 2 mentions across 2 observed days
  • Momentum state: stable

What's happening

  • Patch or workaround mentioned in 1 signal
  • Technical details provided in 2 signals
  • Disclosure: 1 classified signal
  • Peaked 1d ago at 1 mentions (2026-07-21); latest day: 1
  • 2 total mentions across 2 days

Deep dive

Activity timeline2 mentions / 2d
00111Mentions · 2026-07-21: 1Mentions · 2026-07-23: 1Patch / Workaround · 2026-07-21: 1Technical Details · 2026-07-21: 1Technical Details · 2026-07-23: 107-2107-23
Signal classification2 categories
Patch
150.0%
Disclosure
150.0%
Referenced assets1 URL
Classification over time
DateTotalLabels
2026-07-211
Patch1
2026-07-231
Disclosure1
Full discourse2 posts
  • Windows Forum@windowsforum
    Patch

    🔒 A zero-length Port I/O request can still cause maximum chaos in AMD SEV KVM hosts. CVE-2026-63940 scores 9.3 Critical—patch Linux 6.12.95+ before “no-op” becomes “no uptime.” https://windowsforum.com/threads/cve-2026-63940-patch-amd-sev-kvm-hosts-in-linux-6-12-95.439778/?utm_source=x&utm_medium=social&utm_campaign=news_node84 #LinuxKernel #KernelSecurity #KvmVirtualization #AmdSev https://t.co/n99HlfI4Il

    Post summary

    The message warns of a critical 9.3 CVE-2026-63940 affecting AMD SEV KVM hosts and urges users to update to Linux 6.12.95+ to mitigate the zero‑length Port I/O request vulnerability.

    0100050
    1.3K followersView on X
  • DFIR Lab@DFIR_Lab
    Disclosure

    🚨 CRITICAL: CVE-2026-63940 | CVSS 9.3 Linux kernel KVM SEV vulnerability allows local privilege escalation via Port I/O length '0' handling flaw. Affected: Linux kernel KVM SEV module Impact: Code execution, system compromise #CVE #PatchNow #ThreatIntel https://t.co/yrQTn1FdYw

    Post summary

    The tweet announces CVE-2026-63940, a critical local privilege escalation flaw in Linux kernel KVM SEV, highlighting its severity (CVSS 9.3) and urging prompt patching, but provides no PoC, exploit code, or evidence of active exploitation.

    0000053
    91 followersView on X

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