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CVE Record

CVE-2023-53840: usb: early: xhci-dbc: Fix a potential out-of-bound memory access

In the Linux kernel, the following vulnerability has been resolved: usb: early: xhci-dbc: Fix a potential out-of-bound memory access If xdbc_bulk_write() fails, the values in 'buf' can be anything. So the string is not guaranteed to be NULL terminated when xdbc_trace() is called. Reserve an extra byte, which will be zeroed automatically because 'buf' is a static variable, in order to avoid troubles, should it happen.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2023-53840 is a Linux kernel memory-safety fix in early USB xHCI debug capability code. A failed bulk write can leave a buffer without guaranteed string termination, creating possible out-of-bounds memory access during tracing. Public sources do not provide CVSS, practical impact, or active exploitation evidence.

Executive priority

Treat this as routine kernel hygiene unless your environment uses custom kernels or USB debug capability in sensitive systems. No active exploitation or severity score is provided, so urgency should be driven by exposure, vendor guidance, and normal kernel patch cycles.

Technical view

The issue is in xdbc_bulk_write() and xdbc_trace() handling within usb early xhci-dbc. If the write fails, buffer contents may be arbitrary and not NULL terminated. The upstream fix reserves one extra zeroed byte in the static buffer to prevent out-of-bounds access when tracing treats it as a string.

Likely exposure

Exposure appears limited to Linux kernels containing the affected xhci-dbc code path. The source bundle lists Linux kernel versions/ranges as affected and multiple stable kernel commits as fixes, but does not identify distributions, configurations, or runtime prerequisites beyond the kernel component.

Exploitation context

The bundle marks KEV as false and provides no cited evidence of active exploitation, public exploit code, or weaponized use. The available evidence supports a potential memory access bug, not a confirmed real-world attack path.

Researcher notes

Evidence is sparse: no CVSS, CWE, exploitability analysis, or distribution advisories are included. The fix suggests a defensive bounds/termination correction in tracing after write failure. Further assessment should verify exact affected ranges and whether xhci-dbc is reachable in the target kernel configuration.

Mitigation direction

  • Update affected Linux kernels to vendor builds containing the referenced stable fixes.
  • Check Linux distribution advisories for backported fixes and package-specific status.
  • Prioritize systems using kernel debugging, USB debug, or custom kernel builds.
  • Track CVE Program and kernel stable references for any revised severity data.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and embedded systems.
  • Compare deployed kernels with vendor advisories and the referenced stable commits.
  • Review kernel configuration and boot usage for xhci-dbc or early USB debug features.
  • Confirm patched systems are running the updated kernel after reboot.
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.

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CVE-2023-53840 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
0ADP providers
5Source links

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.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxaeb9dd1de98c1a5f2007ea5d2a154c1244caf8a0, aeb9dd1de98c1a5f2007ea5d2a154c1244caf8a0, aeb9dd1de98c1a5f2007ea5d2a154c1244caf8a0, aeb9dd1de98c1a5f2007ea5d2a154c1244caf8a0unaffected
LinuxLinux4.12, 0, 5.15.99, 6.1.16, 6.2.3, 6.3affected
Weakness

CWE details

No CWE listed

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