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CVE Record

CVE-2021-36148: An issue was discovered in ACRN before 2.5.

An issue was discovered in ACRN before 2.5. dmar_free_irte in hypervisor/arch/x86/vtd.c allows an irte_alloc_bitmap buffer overflow.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2021-36148 is a buffer overflow issue in the ACRN hypervisor before version 2.5. The public record names a specific hypervisor function involved in VT-d handling. Business urgency depends on whether ACRN is used in production; the sources do not provide severity, CVSS, impact detail, or confirmed exploitation.

Executive priority

Set priority after confirming ACRN usage. If ACRN is not present, business exposure is likely none. If ACRN before 2.5 supports sensitive isolation boundaries, prioritize remediation because the issue is in hypervisor memory handling, even though public severity and exploitation evidence are missing.

Technical view

The CVE states that dmar_free_irte in hypervisor/arch/x86/vtd.c allows an irte_alloc_bitmap buffer overflow in ACRN before 2.5. The only technical reference in the bundle is an upstream ACRN commit. No CWE, CVSS vector, privilege requirement, or impact statement is provided.

Likely exposure

Exposure appears limited to environments running ACRN hypervisor versions before 2.5 or downstream forks missing the referenced upstream change. The source bundle does not identify packaged products, distributions, appliances, or cloud services that include the vulnerable code.

Exploitation context

The bundle does not cite active exploitation, public exploit availability, or inclusion in CISA KEV. Treat exploitation status as unconfirmed. The named component is hypervisor-level x86 VT-d code, so validate exposure carefully where ACRN is used for isolation-sensitive workloads.

Researcher notes

The public data is sparse. The strongest facts are the affected range, function name, file path, overflow description, and upstream commit reference. Further analysis should inspect the commit and surrounding ACRN VT-d code, but avoid assuming impact beyond what the sources state.

Mitigation direction

  • Inventory all ACRN hypervisor deployments and downstream forks.
  • Upgrade ACRN versions before 2.5 to 2.5 or later where applicable.
  • Confirm downstream forks include the referenced upstream commit.
  • Review vendor or project release guidance before production rollout.
  • Prioritize systems where ACRN enforces workload isolation.

Validation and detection

  • Check deployed ACRN versions against the before-2.5 affected range.
  • Verify whether commit 25c0e3817eb332660dd63d1d4522e63dcc94e79a is present.
  • Review hypervisor/arch/x86/vtd.c for the corrected dmar_free_irte logic.
  • Confirm x86 VT-d functionality is enabled where ACRN is deployed.
  • Document systems with uncertain fork provenance for follow-up review.
Prepared
Confidence
medium
Sources
3

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

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2021-36148 mapping review

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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
2Source 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

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.