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CVE Record

CVE-2025-21742: usbnet: ipheth: use static NDP16 location in URB

In the Linux kernel, the following vulnerability has been resolved: usbnet: ipheth: use static NDP16 location in URB Original code allowed for the start of NDP16 to be anywhere within the URB based on the `wNdpIndex` value in NTH16. Only the start position of NDP16 was checked, so it was possible for even the fixed-length part of NDP16 to extend past the end of URB, leading to an out-of-bounds read. On iOS devices, the NDP16 header always directly follows NTH16. Rely on and check for this specific format. This, along with NCM-specific minimal URB length check that already exists, will ensure that the fixed-length part of NDP16 plus a set amount of DPEs fit within the URB. Note that this commit alone does not fully address the OoB read. The limit on the amount of DPEs needs to be enforced separately.

HighCVSS 7.1Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue can let a local, low-privileged attacker trigger out-of-bounds reads in the ipheth USB networking driver. The likely impact is sensitive memory disclosure or a crash. The sources do not show internet-facing exposure or confirmed active exploitation.

Executive priority

Treat as high priority for managed Linux fleets with USB networking exposure. It is not shown as remotely exploitable or actively exploited, but the memory disclosure and crash potential justify timely patch validation.

Technical view

The bug is CWE-125 in usbnet ipheth NCM parsing. NDP16 placement was derived from wNdpIndex, and only the NDP16 start was checked, allowing the fixed NDP16 area to extend beyond the URB. The fix constrains NDP16 to the static iOS format, but notes separate DPE count limits are also required.

Likely exposure

Exposure appears limited to Linux systems running affected kernels where the ipheth USB network path is reachable, such as iOS USB tethering scenarios. The source bundle lists Linux kernel versions/statuses but does not provide distro package names or complete downstream backport status.

Exploitation context

The CVSS vector is local, low complexity, low privileges, and no user interaction, with high confidentiality and availability impact. KEV is false, and the provided sources do not cite public exploitation.

Researcher notes

The key nuance is that the cited commit narrows NDP16 placement but explicitly says it does not fully address the out-of-bounds read alone. Validation should check the complete upstream or distro patch set, not only this commit.

Mitigation direction

  • Apply Linux kernel updates containing the referenced stable commits.
  • Check your Linux distribution advisory for backported fixes.
  • Prioritize systems that use ipheth or iOS USB tethering workflows.
  • If updates are unavailable, follow vendor guidance for reducing ipheth exposure.

Validation and detection

  • Inventory Linux kernel versions across managed endpoints and servers.
  • Identify hosts where the ipheth module or iOS USB tethering is used.
  • Confirm installed kernel includes the relevant stable fix commits or distro backport.
  • Track whether the separate DPE count limit fix is also present.
Prepared
Confidence
medium
Sources
6

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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cwe · low confidence lookup

CWE-125: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2025-21742 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.1 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

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.

1CVSS vectors
3Timeline events
1ADP providers
5Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.1CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H1.85.2CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

7.1High
CVSS 3.1 vector shape for CVE-2025-21742Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

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
cvssV3_1other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxa2d274c62e44b1995c170595db3865c6fe701226, a2d274c62e44b1995c170595db3865c6fe701226, a2d274c62e44b1995c170595db3865c6fe701226, a2d274c62e44b1995c170595db3865c6fe701226unaffected
LinuxLinux6.5, 0, 6.6.78, 6.12.14, 6.13.3, 6.14affected
Weakness

CWE details

CWE-125

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-125 · source CWE mapping

Out-of-bounds Read

Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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