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CVE Record

CVE-2021-38202: fs/nfsd/trace.h in the Linux kernel before 5.13.4 might allow remote attackers to cause a denial of service...

fs/nfsd/trace.h in the Linux kernel before 5.13.4 might allow remote attackers to cause a denial of service (out-of-bounds read in strlen) by sending NFS traffic when the trace event framework is being used for nfsd.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This flaw can let remote NFS traffic crash or disrupt a Linux kernel under a specific condition: nfsd tracing is in use. It is a denial-of-service issue, not a documented data theft or code execution issue. Public sources do not show active exploitation.

Executive priority

Treat as a targeted availability risk for NFS-dependent infrastructure. Prioritize systems that expose NFS broadly or support critical file services, especially where operational tracing is enabled.

Technical view

CVE-2021-38202 is an out-of-bounds read in fs/nfsd/trace.h before Linux kernel 5.13.4. The issue is reachable through NFS traffic when the trace event framework is being used for nfsd, causing a possible denial of service via strlen behavior.

Likely exposure

Exposure is most likely on Linux systems running kernels before 5.13.4, operating as NFS servers, with nfsd trace events enabled or used. Vendor appliance exposure should be checked against NetApp and Siemens advisories.

Exploitation context

The CVE description says remote attackers might cause denial of service through NFS traffic. The provided sources do not identify public exploit code, exploitation in the wild, or CISA KEV listing.

Researcher notes

The public record is sparse: no CVSS, CWE, or detailed affected product list is provided in the bundle. The strongest technical indicators are the kernel commit, Linux 5.13.4 changelog, and conditional nfsd tracing requirement.

Mitigation direction

  • Upgrade affected Linux kernels to 5.13.4 or a vendor-fixed build.
  • Check NetApp and Siemens advisories for product-specific status and fixes.
  • Limit NFS service exposure to trusted networks where operationally possible.
  • Avoid unnecessary nfsd tracing on unpatched systems until vendor guidance is applied.

Validation and detection

  • Inventory Linux NFS servers and record kernel versions.
  • Confirm whether nfsd tracing is enabled or actively used.
  • Compare appliance versions against NetApp and Siemens advisory status.
  • Verify patched systems run kernel 5.13.4 or vendor-fixed equivalents.
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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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

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

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ADP provider summaries

CVECVE Program Container
siemens-SADPADP container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

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