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CVE Record

CVE-2021-47539: rxrpc: Fix rxrpc_peer leak in rxrpc_look_up_bundle()

In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix rxrpc_peer leak in rxrpc_look_up_bundle() Need to call rxrpc_put_peer() for bundle candidate before kfree() as it holds a ref to rxrpc_peer. [DH: v2: Changed to abstract out the bundle freeing code into a function]

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue is a reference-count leak in the RXRPC networking code. In practical terms, affected systems may leak kernel peer objects under relevant RXRPC activity. The source bundle does not provide CVSS, impact severity, or evidence of active exploitation.

Executive priority

Track this as a kernel maintenance item unless your environment depends on RXRPC-related functionality. There is insufficient evidence to justify emergency handling, but affected kernels should be brought onto supported fixed builds.

Technical view

CVE-2021-47539 fixes missing rxrpc_put_peer() handling in rxrpc_look_up_bundle() before freeing a bundle candidate. The bug leaves an rxrpc_peer reference held, causing a kernel object leak. The public record lists Linux kernel impact and stable kernel commits resolving the flaw.

Likely exposure

Exposure is most relevant to Linux systems running affected kernel versions with RXRPC functionality present or used. The bundle references 5.10, 5.10.84, 5.15.7, and 5.16 context, but distribution backports must be checked directly.

Exploitation context

The provided sources do not show active exploitation, public weaponization, KEV listing, exploit prerequisites, or attacker impact details. Treat exploitability as unproven from this evidence rather than absent.

Researcher notes

The evidence supports a memory/reference leak fix, not a confirmed privilege escalation or remote code execution claim. Key gaps are missing CVSS, CWE, detailed impact, and exploitability analysis in the supplied public data.

Mitigation direction

  • Check the Linux vendor advisory or kernel package notes for CVE-2021-47539.
  • Update to a vendor-supported kernel containing the referenced RXRPC fix.
  • Prioritize systems using RXRPC, AFS, or related kernel networking features.
  • If no fix is available, follow vendor mitigation guidance rather than applying ad hoc changes.

Validation and detection

  • Inventory running kernel versions and vendor package build identifiers.
  • Confirm whether RXRPC support is enabled or used on exposed systems.
  • Verify the kernel changelog references CVE-2021-47539 or the stable commits.
  • Regression test RXRPC or AFS workloads after kernel updates.
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

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CVE-2021-47539 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

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux245500d853e9f20036cec7df4f6984ece4c6bf26, 245500d853e9f20036cec7df4f6984ece4c6bf26, 245500d853e9f20036cec7df4f6984ece4c6bf26unaffected
LinuxLinux5.10, 0, 5.10.84, 5.15.7, 5.16affected
Weakness

CWE details

No CWE listed

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