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CVE Record

CVE-2021-47398: RDMA/hfi1: Fix kernel pointer leak

In the Linux kernel, the following vulnerability has been resolved: RDMA/hfi1: Fix kernel pointer leak Pointers should be printed with %p or %px rather than cast to 'unsigned long long' and printed with %llx. Change %llx to %p to print the secured pointer.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel information disclosure issue in the RDMA hfi1 driver. The bug printed a kernel pointer in a less-protected format, which can expose memory address information. That kind of leak usually matters because it can help bypass defenses, but the provided sources do not show active exploitation or business impact details.

Executive priority

Treat this as a routine kernel maintenance issue unless RDMA/hfi1 is used in sensitive environments. There is no cited active exploitation, no CVSS score, and no evidence of standalone compromise, but patching is still prudent because kernel address leaks can weaken platform hardening.

Technical view

CVE-2021-47398 fixes RDMA/hfi1 pointer formatting by replacing an unsigned long long %llx print with %p, so the kernel uses secured pointer output behavior. The source bundle identifies affected Linux versions around 5.13 through 5.15 and references two stable kernel commits. No CVSS, CWE, or exploit evidence is provided.

Likely exposure

Exposure appears limited to Linux systems running affected kernel versions with the RDMA hfi1 code present and reachable. The source bundle does not identify distributions, appliances, cloud images, or package names, so product-level exposure must be confirmed through vendor kernel advisories and local inventory.

Exploitation context

The provided sources do not report active exploitation, and the CVE is not listed as KEV in the bundle. The issue is an information leak, not a directly documented remote code execution path. Its main concern is potential support for other kernel exploitation chains.

Researcher notes

The evidence is sparse: the CVE description only documents a pointer-printing fix in RDMA/hfi1. Avoid expanding scope beyond Linux kernel hfi1 without vendor confirmation. Key research tasks are mapping downstream backports, affected distro kernels, and whether local logging paths expose the pointer output to unprivileged users.

Mitigation direction

  • Check Linux distribution or kernel vendor guidance for CVE-2021-47398.
  • Upgrade to a vendor kernel that includes the referenced stable fixes.
  • Prioritize systems using RDMA/hfi1 functionality or affected kernel branches.
  • Track scanner findings until patched kernels are deployed and verified.

Validation and detection

  • Inventory Linux kernel versions across servers and images.
  • Identify systems where RDMA/hfi1 support is present or used.
  • Confirm the running kernel includes one of the referenced stable commits or vendor backport.
  • Review vulnerability scanner output for CVE-2021-47398 after remediation.
Prepared
Confidence
medium
Sources
4

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-2021-47398 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
3Source 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
LinuxLinux042a00f93aad5874937e00f36e68301f7e3a0af1, 042a00f93aad5874937e00f36e68301f7e3a0af1unaffected
LinuxLinux5.13, 0, 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.