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CVE Record

CVE-2021-47207: ALSA: gus: fix null pointer dereference on pointer block

In the Linux kernel, the following vulnerability has been resolved: ALSA: gus: fix null pointer dereference on pointer block The pointer block return from snd_gf1_dma_next_block could be null, so there is a potential null pointer dereference issue. Fix this by adding a null check before dereference.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2021-47207 is a Linux kernel issue in the ALSA GUS sound driver. A missing null check could let the kernel dereference a null pointer. The public record does not provide severity, CVSS, confirmed impact, or active exploitation evidence.

Executive priority

Treat this as routine kernel hygiene unless your environment uses or exposes legacy ALSA GUS support. Escalate priority for shared Linux systems with untrusted local users after confirming affected kernel configuration.

Technical view

The flaw is in ALSA gus handling around snd_gf1_dma_next_block. The returned pointer block may be null, but the vulnerable code could dereference it. Kernel stable commits fix this by checking for null before use.

Likely exposure

Exposure appears limited to Linux systems running affected kernel builds where the ALSA GUS driver code is present and reachable. The bundle lists affected Linux kernel versions and multiple stable fix commits, but does not describe configuration prerequisites or attack surface.

Exploitation context

The source bundle marks KEV as false and cites no active exploitation. It also does not provide a public exploit, attacker requirements, privilege requirements, or whether the likely result is only denial of service.

Researcher notes

The record supports a null pointer dereference in the Linux ALSA GUS driver and fixes via stable commits. It does not establish exploitability, impact scope, or a CVSS score, so assessment should remain evidence-bound.

Mitigation direction

  • Move affected Linux kernels to a vendor-supported fixed kernel release.
  • Prioritize systems where ALSA GUS support is enabled, loaded, or available to untrusted users.
  • Check distribution advisories for backported fixes matching the cited stable commits.
  • If patching is delayed, review vendor guidance for disabling unused ALSA GUS support.

Validation and detection

  • Inventory Linux kernel versions across servers, workstations, and appliances.
  • Check whether ALSA GUS-related kernel modules or built-in support are present.
  • Compare installed kernel packages against distribution advisories and fixed stable commits.
  • Confirm vulnerability scanner findings map to CVE-2021-47207, not only generic kernel age.
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-2021-47207 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
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2unaffected
LinuxLinux2.6.12, 0, 4.4.293, 4.9.291, 4.14.256, 4.19.218, 5.4.162, 5.10.82, 5.15.5, 5.16affected
Weakness

CWE details

No CWE listed

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