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CVE Record

CVE-2021-47528: usb: cdnsp: Fix a NULL pointer dereference in cdnsp_endpoint_init()

In the Linux kernel, the following vulnerability has been resolved: usb: cdnsp: Fix a NULL pointer dereference in cdnsp_endpoint_init() In cdnsp_endpoint_init(), cdnsp_ring_alloc() is assigned to pep->ring and there is a dereference of it in cdnsp_endpoint_init(), which could lead to a NULL pointer dereference on failure of cdnsp_ring_alloc(). Fix this bug by adding a check of pep->ring. This bug was found by a static analyzer. The analysis employs differential checking to identify inconsistent security operations (e.g., checks or kfrees) between two code paths and confirms that the inconsistent operations are not recovered in the current function or the callers, so they constitute bugs. Note that, as a bug found by static analysis, it can be a false positive or hard to trigger. Multiple researchers have cross-reviewed the bug. Builds with CONFIG_USB_CDNSP_GADGET=y show no new warnings, and our static analyzer no longer warns about this code.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel denial-of-service class issue in the USB CDNDP gadget driver path. A failed memory allocation could be dereferenced as NULL, potentially crashing the kernel. The source says it was found by static analysis, may be hard to trigger, and has no cited evidence of active exploitation.

Executive priority

Treat as targeted operational risk, not broad emergency. Prioritize embedded, appliance, or USB-gadget Linux assets, then remediate through normal kernel update channels once exposure is confirmed.

Technical view

In cdnsp_endpoint_init(), cdnsp_ring_alloc() assigns pep->ring, then code later dereferences it without confirming allocation succeeded. The fix adds a pep->ring check. Evidence points to CONFIG_USB_CDNSP_GADGET builds and Linux kernel versions identified in the CVE record.

Likely exposure

Exposure appears limited to Linux systems using affected kernel versions with the CDNDP USB gadget driver enabled or reachable. Typical business servers are less likely exposed unless they run this kernel configuration or embedded USB gadget hardware.

Exploitation context

No KEV listing and no provided source claims active exploitation. The CVE description says the issue was found by static analysis and may be a false positive or hard to trigger, though cross-reviewed by researchers.

Researcher notes

The record lacks CVSS, CWE, and concrete trigger details. Avoid assuming remote exploitability. Focus validation on kernel version, driver configuration, and whether downstream distributions backported the null-check fix.

Mitigation direction

  • Apply Linux vendor kernel updates containing the referenced stable fixes.
  • Prioritize systems with CONFIG_USB_CDNSP_GADGET enabled or USB gadget roles.
  • Check distribution advisories for backported fixes and supported package versions.
  • If updates are unavailable, consult vendor guidance for disabling unused USB gadget support.

Validation and detection

  • Inventory Linux kernel versions against the CVE affected data.
  • Check kernel configuration for CONFIG_USB_CDNSP_GADGET.
  • Confirm deployed kernels include one of the linked stable fixes or vendor backports.
  • Review crash logs for CDNDP or USB gadget kernel NULL dereference traces.
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

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.

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CVE-2021-47528 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

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux3d82904559f4f5a2622db1b21de3edf2eded7664, 3d82904559f4f5a2622db1b21de3edf2eded7664unaffected
LinuxLinux5.12, 0, 5.15.7, 5.16affected
Weakness

CWE details

No CWE listed

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