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CVE Record

CVE-2021-38201: net/sunrpc/xdr.c in the Linux kernel before 5.13.4 allows remote attackers to cause a denial of service (xd...

net/sunrpc/xdr.c in the Linux kernel before 5.13.4 allows remote attackers to cause a denial of service (xdr_set_page_base slab-out-of-bounds access) by performing many NFS 4.2 READ_PLUS operations.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-38201 is a Linux kernel flaw that can let a remote attacker crash or disrupt systems using NFS 4.2. The public record ties the issue to repeated READ_PLUS operations and says kernels before 5.13.4 are affected. There is no provided evidence of active exploitation.

Executive priority

Handle as a service availability risk, not confirmed data theft. Prioritize externally reachable or business-critical NFS servers, then vendor appliances using affected Linux kernels. The absence of KEV evidence lowers emergency pressure, but reachable NFS infrastructure should not remain unpatched.

Technical view

The issue is in Linux net/sunrpc/xdr.c and involves slab out-of-bounds access in xdr_set_page_base during many NFS 4.2 READ_PLUS operations. The upstream fix is referenced in Linux 5.13.4 and a specific kernel commit. CVSS, CWE, and detailed affected-product metadata are not provided.

Likely exposure

Exposure is most likely on Linux systems or vendor appliances using affected kernels with NFS 4.2 reachable by untrusted or broad network sources. Exact product exposure beyond upstream Linux and the referenced NetApp advisory is not established in the provided bundle.

Exploitation context

The source bundle supports remote denial of service risk through NFS 4.2 READ_PLUS activity. It does not show public exploit code, active exploitation, or inclusion in CISA KEV. Treat internet-exposed or broadly reachable NFS services as the higher-priority scenario.

Researcher notes

Evidence is sparse: no CVSS, CWE, CPE, or detailed vendor affected matrix is included. The strongest technical anchors are the Linux 5.13.4 changelog, the upstream commit, and the CVE description. Avoid assuming affected NetApp products without reading the linked advisory.

Mitigation direction

  • Upgrade Linux kernels to 5.13.4 or a vendor release carrying the upstream fix.
  • Check NetApp and other vendor advisories for product-specific affected versions and fixes.
  • Limit NFS service reachability to trusted networks and approved clients.
  • Prioritize remediation for systems where NFS 4.2 is exposed across security boundaries.

Validation and detection

  • Inventory Linux hosts and appliances providing NFS services.
  • Confirm kernel versions or vendor kernel errata include the referenced fix.
  • Identify whether NFS 4.2 is enabled and reachable from untrusted networks.
  • Review crash, panic, or service disruption logs on exposed NFS servers.
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
0Timeline events
0ADP providers
4Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

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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