LiveActive security incident?Get immediate response
CVE Record

CVE-2021-47407: KVM: x86: Handle SRCU initialization failure during page track init

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Handle SRCU initialization failure during page track init Check the return of init_srcu_struct(), which can fail due to OOM, when initializing the page track mechanism. Lack of checking leads to a NULL pointer deref found by a modified syzkaller. [Move the call towards the beginning of kvm_arch_init_vm. - Paolo]

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

Security readout for executives and security teams

Plain-English summary

This is a Linux KVM x86 kernel bug where an out-of-memory failure during VM page-tracking setup was not handled, leading to a NULL pointer dereference. The public record does not provide CVSS, confirmed impact severity, or evidence of active exploitation.

Executive priority

Treat as a kernel reliability and availability risk for virtualization infrastructure. Prioritize patch confirmation on KVM hosts, but avoid emergency escalation unless vendor advisories add severity, exploitability, or business-specific exposure evidence.

Technical view

KVM x86 page-track initialization failed to check init_srcu_struct() return status. If SRCU initialization failed, reportedly due to OOM, later code could dereference NULL. The Linux stable references identify patches that handle the initialization failure earlier in kvm_arch_init_vm.

Likely exposure

Exposure appears limited to Linux systems running affected kernel versions with KVM x86 virtualization paths. The supplied CVE data lists Linux as affected but does not provide precise distribution package mappings or complete fixed version ranges.

Exploitation context

The issue was found by a modified syzkaller. The CVE is not listed as KEV in the supplied bundle, and no cited source claims active exploitation or public weaponization.

Researcher notes

The public evidence supports a KVM x86 NULL pointer dereference caused by unchecked SRCU initialization failure. Impact details, attacker prerequisites, and affected distribution packages are not supplied. Avoid assuming guest-to-host compromise from this record alone.

Mitigation direction

  • Check Linux distribution advisories for CVE-2021-47407 package status.
  • Update affected kernels to builds containing the referenced Linux stable fixes.
  • Prioritize KVM virtualization hosts and systems that create VMs under memory pressure.
  • If no vendor fix is available, follow vendor guidance for risk reduction.

Validation and detection

  • Inventory Linux kernel versions on KVM x86 hosts.
  • Confirm vendor kernel changelogs include CVE-2021-47407 or the referenced commits.
  • Run authenticated vulnerability scanning against virtualization hosts.
  • Verify no local policy treats non-KEV kernel CVEs as emergency exceptions.
Prepared
Confidence
medium
Sources
5

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-2021-47407 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
4Source 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
LinuxLinux0eb05bf290cfe8610d9680b49abef37febd1c38a, 0eb05bf290cfe8610d9680b49abef37febd1c38a, 0eb05bf290cfe8610d9680b49abef37febd1c38aunaffected
LinuxLinux4.6, 0, 5.10.71, 5.14.10, 5.15affected
Weakness

CWE details

No CWE listed

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