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CVE Record

CVE-2021-47058: regmap: set debugfs_name to NULL after it is freed

In the Linux kernel, the following vulnerability has been resolved: regmap: set debugfs_name to NULL after it is freed There is a upstream commit cffa4b2122f5("regmap:debugfs: Fix a memory leak when calling regmap_attach_dev") that adds a if condition when create name for debugfs_name. With below function invoking logical, debugfs_name is freed in regmap_debugfs_exit(), but it is not created again because of the if condition introduced by above commit. regmap_reinit_cache() regmap_debugfs_exit() ... regmap_debugfs_init() So, set debugfs_name to NULL after it is freed.

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 memory handling bug in the regmap debugfs cleanup and reinitialization path. A freed debugfs_name pointer was not cleared, so later initialization could treat stale memory as valid. Public sources do not provide CVSS, impact detail, or evidence of active exploitation.

Executive priority

Treat this as routine kernel maintenance unless internal context raises exposure. There is no public exploitation evidence or severity score in the provided sources, but kernel memory defects should still be closed through normal patch governance.

Technical view

The regmap_debugfs_exit() path frees debugfs_name, but prior logic could prevent regmap_debugfs_init() from recreating it because the pointer still appeared set. The fix sets debugfs_name to NULL after free. The affected data lists Linux kernel versions and stable commit ranges, but gives no CWE or exploitability assessment.

Likely exposure

Exposure is limited to systems running affected Linux kernels with the regmap debugfs reinitialization path reachable. The source bundle does not identify specific distributions, device classes, configurations, or public-facing services as affected.

Exploitation context

The CVE is not listed as KEV in the provided bundle, and no cited source reports active exploitation. The available record describes a kernel memory lifecycle defect, not a remote exploit path or attacker prerequisites.

Researcher notes

The record centers on regmap_debugfs_exit(), regmap_debugfs_init(), and regmap_reinit_cache() behavior after upstream commit cffa4b2122f5. Evidence supports a stale freed pointer condition. Impact, attacker control, and reachable configurations are not established in the provided sources.

Mitigation direction

  • Update to a vendor-supported kernel containing the referenced stable fixes.
  • Check your Linux distribution advisory for backported CVE-2021-47058 coverage.
  • Prioritize kernel updates on systems using affected 4.19, 5.4, 5.10, 5.11, 5.12, or 5.13 lines.
  • Avoid assuming configuration workarounds unless vendor guidance explicitly recommends them.

Validation and detection

  • Inventory running kernel versions across Linux hosts and appliances.
  • Compare installed kernels with vendor advisories and the referenced stable commits.
  • Confirm patched kernels are booted, not only installed.
  • Record exceptions where vendor support status or backport evidence is unclear.
Prepared
Confidence
medium
Sources
8

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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CVE-2021-47058 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
7Source 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
LinuxLinux5b654b03007917f3f1015b2a5c288c1ea6ae8f65, 480c5e9c7e4c76c01d5f1f7b73832d7b77e6b427, c9698380b01aed3281160d3ab25749b57d6913b8, cffa4b2122f5f3e53cf3d529bbc74651f95856d5, cffa4b2122f5f3e53cf3d529bbc74651f95856d5, cffa4b2122f5f3e53cf3d529bbc74651f95856d5unaffected
LinuxLinux5.11, 0, 4.19.191, 5.4.119, 5.10.37, 5.11.21, 5.12.4, 5.13affected
Weakness

CWE details

No CWE listed

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