LiveActive security incident?Get immediate response
CVE Record

CVE-2021-47049: Drivers: hv: vmbus: Use after free in __vmbus_open()

In the Linux kernel, the following vulnerability has been resolved: Drivers: hv: vmbus: Use after free in __vmbus_open() The "open_info" variable is added to the &vmbus_connection.chn_msg_list, but the error handling frees "open_info" without removing it from the list. This will result in a use after free. First remove it from the list, and then free it.

UnknownCVSS not scoredNot KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2021-47049 is a Linux kernel bug in the Hyper-V VMBus driver. An error path could free a tracking object while it remained on a shared list, creating a use-after-free condition. The public bundle does not provide CVSS scoring, confirmed impact, or active exploitation evidence.

Executive priority

Schedule remediation through the normal kernel patch process, with higher priority for Linux workloads on Hyper-V-style virtualization. Current public evidence does not support emergency treatment, but kernel use-after-free issues deserve timely closure.

Technical view

In __vmbus_open(), open_info is added to vmbus_connection.chn_msg_list. On an error path, it was freed without first being removed from that list. The fix removes it from the list before freeing, preventing later use of stale memory.

Likely exposure

Exposure is most relevant to Linux systems running affected kernel versions or commits that include the hv/vmbus driver code. The source identifies Linux as the affected product and references stable kernel fixes, but does not identify affected distributions or downstream package versions.

Exploitation context

The bundle marks KEV as false and gives no cited evidence of active exploitation. It also does not provide exploit prerequisites, attack path, or practical impact. Treat this as a kernel memory-safety issue requiring patch tracking, not as a confirmed in-the-wild emergency.

Researcher notes

The available record is sparse: no CVSS, CWE, exploit details, or distribution matrix. Analysis should stay tied to the listed Linux kernel commits and the described list-management flaw in __vmbus_open(). Confirm downstream exposure through vendor source packages or advisories.

Mitigation direction

  • Update to a vendor-supported Linux kernel containing the referenced stable fix.
  • Check Linux distribution advisories for backported fixed package versions.
  • Prioritize systems using Hyper-V VMBus functionality or affected kernel branches.
  • Avoid direct deployment from upstream commits unless that matches your kernel support model.

Validation and detection

  • Inventory kernel versions across Linux hosts and images.
  • Confirm whether the running kernel includes the stable fix or downstream backport.
  • Review vendor advisories for distribution-specific affected and fixed versions.
  • Validate patched kernels in staging before broad rollout.
  • Monitor kernel logs after update for Hyper-V VMBus regressions.
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

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cve · low confidence lookup

CVE-2021-47049 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
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

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux6f3d791f300618caf82a2be0c27456edd76d5164, 6f3d791f300618caf82a2be0c27456edd76d5164, 6f3d791f300618caf82a2be0c27456edd76d5164, 6f3d791f300618caf82a2be0c27456edd76d5164, 6b32d45bd59982751beb8220e442b40b2706647funaffected
LinuxLinux4.14, 0, 5.10.37, 5.11.21, 5.12.4, 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.