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CVE Record

CVE-2021-47604: vduse: check that offset is within bounds in get_config()

In the Linux kernel, the following vulnerability has been resolved: vduse: check that offset is within bounds in get_config() This condition checks "len" but it does not check "offset" and that could result in an out of bounds read if "offset > dev->config_size". The problem is that since both variables are unsigned the "dev->config_size - offset" subtraction would result in a very high unsigned value. I think these checks might not be necessary because "len" and "offset" are supposed to already have been validated using the vhost_vdpa_config_validate() function. But I do not know the code perfectly, and I like to be safe.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2021-47604 is a Linux kernel issue in VDUSE configuration handling. A missing offset bounds check could allow an out-of-bounds read in a specific kernel path. The public bundle does not provide impact details, CVSS, or active exploitation evidence, so business urgency depends on whether affected kernels and VDUSE/vDPA functionality are present.

Executive priority

Handle through normal kernel vulnerability management unless local use of VDUSE/vDPA is confirmed. Escalate if affected kernels support virtualization infrastructure or shared-host workloads, because kernel memory-read bugs can have higher operational sensitivity.

Technical view

The flaw is in vduse get_config(). The code checked len but not offset; with unsigned arithmetic, offset greater than dev->config_size could make dev->config_size - offset wrap to a very large value, enabling an out-of-bounds read. The kernel fix adds offset validation. Affected version data in the bundle points to Linux 5.15-era releases.

Likely exposure

Exposure is most likely on Linux systems running affected 5.15-era kernels where the VDUSE/vDPA code path is available or used. The source bundle does not confirm default reachability, required privileges, attack vector, or affected distribution packages.

Exploitation context

The provided sources do not show active exploitation, and KEV is false. They also do not include a public exploit, weaponized path, or attacker prerequisites. Treat exploitability as unconfirmed from this bundle alone.

Researcher notes

Evidence is limited to the CVE record and two Linux stable commit references. No CVSS, CWE, exploit status, or distribution-specific fixed versions are provided. The vulnerable condition is an unchecked offset leading to unsigned underflow and possible out-of-bounds read in get_config().

Mitigation direction

  • Apply Linux kernel updates that include the referenced stable fixes.
  • Check distribution advisories for exact fixed kernel package versions.
  • Prioritize systems using VDUSE, vDPA, or virtualization datapath features.
  • Document any unpatched affected kernels and compensating operational controls.

Validation and detection

  • Inventory Linux kernel versions, focusing on 5.15-era systems.
  • Verify whether installed kernels include the referenced stable commits.
  • Confirm whether VDUSE or vDPA functionality is enabled or used.
  • Track remediation against vendor package advisories, not only upstream commits.
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

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CVE-2021-47604 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

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxc8a6153b6c59d95c0e091f053f6f180952ade91e, c8a6153b6c59d95c0e091f053f6f180952ade91eunaffected
LinuxLinux5.15, 0, 5.15.11, 5.16affected
Weakness

CWE details

No CWE listed

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