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CVE Record

CVE-2022-48938: CDC-NCM: avoid overflow in sanity checking

In the Linux kernel, the following vulnerability has been resolved: CDC-NCM: avoid overflow in sanity checking A broken device may give an extreme offset like 0xFFF0 and a reasonable length for a fragment. In the sanity check as formulated now, this will create an integer overflow, defeating the sanity check. Both offset and offset + len need to be checked in such a manner that no overflow can occur. And those quantities should be unsigned.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2022-48938 is a Linux kernel flaw in CDC-NCM USB networking handling. A malformed or broken device can provide extreme fragment offsets that overflow a sanity check, allowing invalid data to pass checks. The source does not provide CVSS, impact details, or evidence of active exploitation.

Executive priority

Treat this as a kernel maintenance issue with higher priority for environments where users or attackers can connect USB networking devices. No active exploitation is cited, so urgency should be driven by exposure to untrusted peripherals and normal kernel patch cycles.

Technical view

The CDC-NCM code performed offset plus length validation in a way that could overflow, defeating bounds checking. The fix checks both offset and offset plus length without overflow and treats the quantities as unsigned. Affected Linux kernel versions are listed in the CVE data, but distribution backport status must be confirmed separately.

Likely exposure

Exposure is most likely on Linux systems using CDC-NCM USB network devices or modem-style networking. Risk depends on kernel version, whether the driver is present or loaded, and whether untrusted or faulty devices can be connected.

Exploitation context

The source describes a broken device supplying an extreme offset, not a remote network exploit. KEV is false, and the provided sources do not claim public exploitation, exploit availability, or real-world attacks.

Researcher notes

The evidence is limited to the CVE record and kernel stable commit references. The vulnerable condition is an integer overflow in CDC-NCM fragment sanity checking. No CWE, CVSS, exploit status, or concrete post-overflow impact is provided in the bundle.

Mitigation direction

  • Update to a vendor-supported kernel containing the referenced stable fixes.
  • Check distribution advisories for backported fixes before relying on upstream version numbers.
  • Limit use of untrusted CDC-NCM USB network devices until patched.
  • Disable or avoid loading CDC-NCM support where it is not operationally needed.

Validation and detection

  • Inventory Linux kernel versions across affected systems.
  • Check whether CDC-NCM USB networking is enabled, loaded, or required.
  • Confirm the kernel package includes one of the referenced stable fixes or a vendor backport.
  • Prioritize validation on systems accepting physical or peripheral device connections.
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

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-2022-48938 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
1ADP 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

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux4ca8b8855264cf1439cdab3da7049bd1e3c2a9e6, a270ca35a9499b58366d696d3290eaa4697a42db, 0fa81b304a7973a499f844176ca031109487dd31, 0fa81b304a7973a499f844176ca031109487dd31, 0fa81b304a7973a499f844176ca031109487dd31, 0fa81b304a7973a499f844176ca031109487dd31, 8cf7db86a8984ffa3a3388a8df12bc0aa4c79bd7unaffected
LinuxLinux5.7, 0, 4.19.323, 5.4.285, 5.10.103, 5.15.26, 5.16.12, 5.17affected
Weakness

CWE details

No CWE listed

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