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CVE Record

CVE-2021-47526: serial: liteuart: Fix NULL pointer dereference in ->remove()

In the Linux kernel, the following vulnerability has been resolved: serial: liteuart: Fix NULL pointer dereference in ->remove() drvdata has to be set in _probe() - otherwise platform_get_drvdata() causes null pointer dereference BUG in _remove().

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel bug in the LiteUART serial driver. If the driver is removed after being loaded, missing driver data can trigger a NULL pointer dereference and kernel BUG. The provided sources do not show remote exposure, privilege requirements, CVSS scoring, or active exploitation.

Executive priority

Treat as targeted operational risk, not an emergency based on available evidence. Prioritize patching for systems using LiteUART or affected custom kernels, and track vendor guidance where standard distribution kernels are deployed.

Technical view

The LiteUART platform driver failed to set drvdata during probe. Its remove path later calls platform_get_drvdata(), which can return NULL and cause a NULL pointer dereference. The kernel stable references identify fixes for this driver lifecycle bug.

Likely exposure

Likely limited to systems running affected Linux kernel versions with the LiteUART serial driver built in or loadable and used. Exposure is unclear for generic servers unless this driver is present. The source bundle does not name distributions, configurations, or CPEs.

Exploitation context

CISA KEV is false, and the supplied sources do not report active exploitation. The described impact is a kernel BUG from a driver remove path, suggesting local or operational trigger conditions, but the sources do not define an attacker model.

Researcher notes

Evidence is narrow: the CVE text describes only the bug and fix. No CVSS, CWE, exploitability analysis, or distribution matrix is provided. Validation should focus on kernel version, LiteUART driver presence, and whether the stable commits are included or backported.

Mitigation direction

  • Identify affected Linux kernels that include the LiteUART driver.
  • Apply kernel updates containing the referenced stable fixes.
  • Check Linux vendor or distribution advisories for backported fixes.
  • Disable or avoid the LiteUART driver where it is unnecessary.

Validation and detection

  • Confirm the running kernel version and vendor patch status.
  • Check whether the LiteUART driver is present, loaded, or built in.
  • Review fleet inventory for affected embedded or FPGA-oriented systems.
  • Verify vendor advisories map the fix to deployed kernels.
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-2021-47526 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
LinuxLinux1da81e5562fac8286567422cc56a7fbd0dc646d4, 1da81e5562fac8286567422cc56a7fbd0dc646d4unaffected
LinuxLinux5.11, 0, 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.