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CVE Record

CVE-2016-20022: In the Linux kernel before 4.8, usb_parse_endpoint in drivers/usb/core/config.c does not validate the wMaxP...

In the Linux kernel before 4.8, usb_parse_endpoint in drivers/usb/core/config.c does not validate the wMaxPacketSize field of an endpoint descriptor. NOTE: This vulnerability only affects products that are no longer supported by the supplier.

HighCVSS 8.4Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This is an old Linux kernel USB parsing flaw. A system running a pre-4.8 kernel could mishandle a malformed USB endpoint descriptor, creating a high-impact local attack risk. The CVE notes affected products are no longer supplier-supported, so practical urgency is mostly legacy asset discovery and replacement.

Executive priority

Treat this as a legacy technology risk, not a broad internet emergency. Prioritize finding unsupported Linux systems and appliances, then upgrade, replace, or isolate them. Business urgency is highest where USB access is plausible and the asset is safety-critical, privileged, or difficult to monitor.

Technical view

In drivers/usb/core/config.c, usb_parse_endpoint did not validate the endpoint descriptor wMaxPacketSize field before Linux 4.8. The issue is classified as CWE-125 with CVSS 8.4 local, unauthenticated, no user-interaction impact. Public sources identify an upstream kernel commit, but affected vendor product mapping is not provided.

Likely exposure

Exposure is most likely on legacy Linux systems or embedded appliances running kernels older than 4.8, especially where USB parsing is reachable. The CVE record states only unsupported supplier products are affected, so modern supported distributions may have backports or be unaffected.

Exploitation context

The CVE is not listed as CISA KEV in the provided bundle, and no source here states active exploitation. The attack vector is local, not remote network exposure. Risk depends on whether an attacker can present untrusted USB descriptor data to the vulnerable kernel.

Researcher notes

The public CVE metadata is sparse: affected vendor/product fields are n/a, and the note limits impact to unsupported products. Analysis should rely on kernel version, downstream backport status, and whether USB descriptor parsing is reachable. Do not assume active exploitation from the provided evidence.

Mitigation direction

  • Upgrade to a supported kernel or vendor-supported product line.
  • Verify the upstream fix or vendor backport is present.
  • Decommission unsupported devices that cannot receive security fixes.
  • Restrict physical and logical access to USB-capable systems.
  • Check vendor guidance for legacy appliances and embedded products.

Validation and detection

  • Inventory Linux kernel versions and flag systems older than 4.8.
  • Confirm whether commit aed9d65ac3278d4febd8665bd7db59ef53e825fe or a vendor backport exists.
  • Identify systems with exposed or usable USB interfaces.
  • Confirm whether any flagged systems are still vendor-supported.
  • Prioritize legacy embedded or appliance systems for replacement review.
Prepared
Confidence
medium
Sources
5

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-2016-20022 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
8.4 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/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
0Timeline events
0ADP providers
4Source links

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
8.4CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H2.55.9Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

8.4High
CVSS 3.1 vector shape for CVE-2016-20022Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

CWE-125

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