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CVE Record

CVE-2020-36311: An issue was discovered in the Linux kernel before 5.9.

An issue was discovered in the Linux kernel before 5.9. arch/x86/kvm/svm/sev.c allows attackers to cause a denial of service (soft lockup) by triggering destruction of a large SEV VM (which requires unregistering many encrypted regions), aka CID-7be74942f184.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This Linux kernel flaw can make affected virtualization hosts stall when a very large AMD SEV-protected VM is destroyed. The business impact is availability, not confirmed data theft. Exposure appears concentrated in KVM environments using AMD SEV on kernels before 5.9 or unpatched vendor kernels.

Executive priority

Treat this as a targeted availability risk for AMD SEV virtualization infrastructure. Patch during the next maintenance window, sooner for multi-tenant or production hypervisors. No source evidence supports emergency response for active exploitation.

Technical view

CVE-2020-36311 is in arch/x86/kvm/svm/sev.c before Linux 5.9. Destroying a large SEV VM can require unregistering many encrypted memory regions and trigger a soft lockup, producing denial of service. The upstream fix is identified as commit 7be74942f184.

Likely exposure

Most relevant exposure is Linux KVM virtualization on x86 AMD SVM/SEV systems running kernels before 5.9 or vendor kernels lacking the backport. The source bundle does not identify broad application-level exposure.

Exploitation context

The bundle does not report active exploitation, and CISA KEV status is false. The described trigger involves destruction of a large SEV VM; the sources do not clearly define required attacker privileges or remote reachability.

Researcher notes

Evidence is sparse: no CVSS, CWE, or detailed affected-version matrix is provided. Focus validation on KVM SVM SEV code paths and vendor backport status rather than product names, because the CVE record lists affected vendor and product as n/a.

Mitigation direction

  • Inventory Linux virtualization hosts running KVM on AMD SVM/SEV-capable hardware.
  • Upgrade to Linux 5.9 or a vendor kernel containing the cited upstream fix.
  • Apply Debian DLA 2714-1 or DSA-4941 where those advisories match deployed systems.
  • Check current distribution security guidance for supported backported kernel packages.
  • Prioritize shared or customer-facing virtualization hosts where host availability is business-critical.

Validation and detection

  • Confirm deployed kernel versions and vendor package release notes against the cited advisories.
  • Verify whether AMD SEV and KVM SVM are enabled on virtualization hosts.
  • Check whether the running kernel includes upstream commit 7be74942f184 or an equivalent backport.
  • Review historical host logs for soft lockup events during SEV VM teardown.
  • Document non-SEV or non-KVM systems as lower relevance, not automatically affected.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
5Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

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