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CVE Record

CVE-2021-47624: net/sunrpc: fix reference count leaks in rpc_sysfs_xprt_state_change

In the Linux kernel, the following vulnerability has been resolved: net/sunrpc: fix reference count leaks in rpc_sysfs_xprt_state_change The refcount leak issues take place in an error handling path. When the 3rd argument buf doesn't match with "offline", "online" or "remove", the function simply returns -EINVAL and forgets to decrease the reference count of a rpc_xprt object and a rpc_xprt_switch object increased by rpc_sysfs_xprt_kobj_get_xprt() and rpc_sysfs_xprt_kobj_get_xprt_switch(), causing reference count leaks of both unused objects. Fix this issue by jumping to the error handling path labelled with out_put when buf matches none of "offline", "online" or "remove".

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This CVE describes a Linux kernel cleanup bug in the SUNRPC subsystem. A failed state-change request can leave internal objects referenced longer than intended. The provided sources do not show active exploitation, CVSS scoring, or a stated business impact, so urgency should be driven by whether affected kernels are deployed on important systems.

Executive priority

Medium operational priority for Linux environments, not an emergency based on current evidence. Patch through normal kernel maintenance unless affected systems are high-value, hard to reboot, or vendor guidance assigns higher severity.

Technical view

In rpc_sysfs_xprt_state_change, invalid input that is not offline, online, or remove returns -EINVAL without releasing references acquired for rpc_xprt and rpc_xprt_switch objects. Upstream fixed this by routing that error path through the existing cleanup path. Affected Linux kernel version data is provided, but exploitability and privilege requirements are not specified.

Likely exposure

Exposure is limited to Linux systems running affected kernel versions identified in the CVE data. The sources point to the kernel SUNRPC area, but they do not define required configuration, local versus remote access, or practical impact. Distribution backports may change version-based exposure.

Exploitation context

The source bundle does not report exploitation in the wild, and KEV is false. No public exploit status, attack path, privilege requirement, or denial-of-service impact is established in the provided evidence. Treat this as a kernel maintenance and exposure-verification item unless vendor advisories add stronger risk signals.

Researcher notes

Evidence supports a reference count leak in an error-handling path, fixed by ensuring cleanup occurs for invalid state strings. The provided record lacks CVSS, CWE, exploitability, reachability, and impact details, so avoid claims beyond memory/resource leak behavior in affected Linux kernels.

Mitigation direction

  • Check distribution advisories for backported fixes matching the upstream stable commits.
  • Update affected Linux kernels to vendor-supported packages containing the SUNRPC refcount fix.
  • Track the referenced upstream stable commits as remediation evidence.
  • Prioritize critical production systems if they run affected kernel builds.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and images.
  • Compare deployed versions with CVE affected data and distribution advisories.
  • Verify kernel package changelogs include the referenced SUNRPC refcount fix.
  • Document systems where exposure cannot be confirmed from available sources.
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

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CVE-2021-47624 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
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
LinuxLinux5b7eb78486cd9ac58bfbd6d84ea0fe2d9fead03b, 5b7eb78486cd9ac58bfbd6d84ea0fe2d9fead03b, 5b7eb78486cd9ac58bfbd6d84ea0fe2d9fead03bunaffected
LinuxLinux5.14, 0, 5.15.24, 5.16.10, 5.17affected
Weakness

CWE details

No CWE listed

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