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CVE Record

CVE-2021-47071: uio_hv_generic: Fix a memory leak in error handling paths

In the Linux kernel, the following vulnerability has been resolved: uio_hv_generic: Fix a memory leak in error handling paths If 'vmbus_establish_gpadl()' fails, the (recv|send)_gpadl will not be updated and 'hv_uio_cleanup()' in the error handling path will not be able to free the corresponding buffer. In such a case, we need to free the buffer explicitly.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel memory leak in the Hyper-V generic UIO driver’s error handling. If a specific VMBus mapping setup fails, cleanup may miss an allocated buffer. The public record does not provide a CVSS score, impact rating, or evidence of active exploitation.

Executive priority

Treat this as a kernel maintenance item with uncertain severity, not as an emergency based on the provided evidence. Ensure affected Linux fleets receive vendor-approved kernel updates through the normal patch cycle.

Technical view

CVE-2021-47071 fixes uio_hv_generic cleanup after vmbus_establish_gpadl() failure. Because the GPADL handle is not updated on failure, hv_uio_cleanup() cannot free the related send or receive buffer, requiring explicit freeing in the error path.

Likely exposure

Exposure is most relevant to Linux systems running affected kernel versions where the uio_hv_generic driver is present or used. The source bundle lists Linux as affected and references stable kernel fixes, but it does not identify specific distributions or deployment scenarios.

Exploitation context

No source in the bundle states active exploitation, public exploit availability, or KEV listing. The described issue is a memory leak triggered by an error path, so urgency should be based on affected kernel presence, vendor advisories, and operational exposure.

Researcher notes

The key condition is failed vmbus_establish_gpadl() before recv_gpadl or send_gpadl is updated, preventing generic cleanup from freeing buffers. The bundle does not provide attack prerequisites, privilege requirements, or practical exploitability details.

Mitigation direction

  • Update to a Linux kernel build containing the referenced stable fixes.
  • Check distribution advisories for the patched package version for CVE-2021-47071.
  • Prioritize hosts using Hyper-V/VMBus-related Linux drivers for review.
  • Track this under routine kernel vulnerability management unless vendor guidance raises severity.

Validation and detection

  • Inventory Linux kernel versions across relevant hosts.
  • Confirm whether vendor kernel packages include the referenced stable commits.
  • Check whether uio_hv_generic is present or used on exposed systems.
  • Review monitoring for unusual memory pressure on affected Hyper-V Linux workloads.
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

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-2021-47071 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
3Timeline events
2ADP providers
5Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxcdfa835c6e5e87d145f9f632b58843de97509f2b, cdfa835c6e5e87d145f9f632b58843de97509f2b, cdfa835c6e5e87d145f9f632b58843de97509f2b, cdfa835c6e5e87d145f9f632b58843de97509f2bunaffected
LinuxLinux4.20, 0, 5.4.122, 5.10.40, 5.12.7, 5.13affected
Weakness

CWE details

No CWE listed

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