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CVE Record

CVE-2021-47518: nfc: fix potential NULL pointer deref in nfc_genl_dump_ses_done

In the Linux kernel, the following vulnerability has been resolved: nfc: fix potential NULL pointer deref in nfc_genl_dump_ses_done The done() netlink callback nfc_genl_dump_ses_done() should check if received argument is non-NULL, because its allocation could fail earlier in dumpit() (nfc_genl_dump_ses()).

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 potential crash bug in the NFC subsystem. If an earlier memory allocation fails, a later netlink cleanup callback may dereference a NULL pointer. The source bundle does not provide CVSS, CWE, or confirmed impact details, so business urgency depends on whether affected kernels and NFC functionality are present.

Executive priority

Treat this as routine-to-elevated kernel maintenance, not an emergency, unless affected systems expose NFC functionality or have many untrusted local users. There is no supplied evidence of active exploitation, but kernel crash bugs still matter for availability and operational resilience.

Technical view

CVE-2021-47518 fixes a missing NULL check in nfc_genl_dump_ses_done(). The done() netlink callback could receive a NULL argument because allocation may fail earlier in nfc_genl_dump_ses(). Stable kernel commits add the defensive handling. The record lists affected Linux versions and multiple stable backport commits.

Likely exposure

Exposure is most likely on Linux systems running affected kernel versions with the NFC kernel subsystem available. The bundle does not identify affected distributions, device classes, required privileges, or whether NFC hardware must be present.

Exploitation context

No active exploitation is supported by the supplied sources. The CVE is not marked KEV, and the bundle provides no public exploit evidence. The described failure mode suggests availability risk from a kernel NULL pointer dereference, but exploitability details are incomplete.

Researcher notes

The key uncertainty is reachability. Sources identify the vulnerable callback and fix rationale, but not prerequisites, privilege level, distribution mappings, or realistic trigger conditions. Validation should focus on kernel lineage, NFC subsystem availability, and whether vendor kernels contain the stable commits.

Mitigation direction

  • Inventory Linux kernel versions across servers, endpoints, appliances, and embedded devices.
  • Prioritize systems where NFC support is enabled or locally reachable.
  • Apply vendor kernel updates containing the referenced stable fixes.
  • If patching is delayed, review vendor guidance for NFC subsystem hardening or disablement.
  • Track distribution advisories that map this kernel fix to package versions.

Validation and detection

  • Confirm running kernel versions against vendor advisories and the CVE record.
  • Check whether NFC kernel modules or configuration are enabled on relevant systems.
  • Verify installed kernel packages include the referenced stable backport fix.
  • Review crash logs for NFC or netlink-related NULL pointer dereference events.
  • Document any systems requiring vendor-specific exception handling.
Prepared
Confidence
medium
Sources
10

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-2021-47518 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
9Source 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
LinuxLinuxac22ac466a659f1b2e02a2e2ee23fc5c42da2c95, ac22ac466a659f1b2e02a2e2ee23fc5c42da2c95, ac22ac466a659f1b2e02a2e2ee23fc5c42da2c95, ac22ac466a659f1b2e02a2e2ee23fc5c42da2c95, ac22ac466a659f1b2e02a2e2ee23fc5c42da2c95, ac22ac466a659f1b2e02a2e2ee23fc5c42da2c95, ac22ac466a659f1b2e02a2e2ee23fc5c42da2c95, ac22ac466a659f1b2e02a2e2ee23fc5c42da2c95unaffected
LinuxLinux3.12, 0, 4.4.295, 4.9.293, 4.14.258, 4.19.221, 5.4.165, 5.10.85, 5.15.8, 5.16affected
Weakness

CWE details

No CWE listed

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