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CVE Record

CVE-2025-40020: can: peak_usb: fix shift-out-of-bounds issue

In the Linux kernel, the following vulnerability has been resolved: can: peak_usb: fix shift-out-of-bounds issue Explicitly uses a 64-bit constant when the number of bits used for its shifting is 32 (which is the case for PC CAN FD interfaces supported by this driver). [mkl: update subject, apply manually]

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2025-40020 is a Linux kernel bug in the PEAK USB CAN driver. The available sources describe an out-of-bounds bit shift fixed by using a 64-bit constant. Business urgency depends on whether Linux hosts use PEAK USB CAN or PC CAN FD hardware.

Executive priority

Treat as targeted operational exposure, not a broad internet emergency. Prioritize environments using CAN bus hardware, especially operational technology, vehicle testing, manufacturing, or embedded Linux deployments.

Technical view

The flaw is in the Linux kernel can: peak_usb driver. For PC CAN FD interfaces, code could shift by 32 bits while using a non-64-bit constant, causing a shift-out-of-bounds condition. The stable kernel references show the issue was resolved across multiple branches.

Likely exposure

Likely limited to Linux systems with the peak_usb CAN driver and supported PEAK USB CAN or PC CAN FD interfaces. The source bundle does not identify remote exposure, privilege requirements, or a broader affected product set.

Exploitation context

The source bundle does not report active exploitation, public exploit availability, or CISA KEV listing. Impact details are also incomplete, so exploitation likelihood and practical consequences cannot be reliably scored from the provided evidence.

Researcher notes

The public record gives the bug class and fix direction but not CVSS, CWE, trigger path, crash behavior, or security boundary. Avoid assuming remote code execution or active abuse without additional vendor or kernel maintainer evidence.

Mitigation direction

  • Identify Linux systems using PEAK USB CAN or PC CAN FD interfaces.
  • Check whether the running kernel includes the relevant stable fix commit.
  • Update to a vendor-supported kernel containing the peak_usb fix.
  • Monitor Linux distribution advisories for package-specific fixed versions.
  • Prioritize industrial, vehicle, lab, or embedded systems using CAN hardware.

Validation and detection

  • Inventory loaded kernel modules and confirm whether peak_usb is present.
  • Map kernel versions against distribution advisories and stable commit backports.
  • Review asset records for attached PEAK-System USB CAN hardware.
  • Confirm patched kernels after maintenance by checking package changelogs.
  • Document systems where the driver exists but hardware is not deployed.
Prepared
Confidence
medium
Sources
10

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-2025-40020 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
9Source 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
LinuxLinuxbb4785551f64e18b2c8bb15a3bd2b22f5ebf624d, bb4785551f64e18b2c8bb15a3bd2b22f5ebf624d, bb4785551f64e18b2c8bb15a3bd2b22f5ebf624d, bb4785551f64e18b2c8bb15a3bd2b22f5ebf624d, bb4785551f64e18b2c8bb15a3bd2b22f5ebf624d, bb4785551f64e18b2c8bb15a3bd2b22f5ebf624d, bb4785551f64e18b2c8bb15a3bd2b22f5ebf624d, bb4785551f64e18b2c8bb15a3bd2b22f5ebf624dunaffected
LinuxLinux3.4, 0, 5.4.300, 5.10.245, 5.15.194, 6.1.155, 6.6.109, 6.12.50, 6.16.10, 6.17affected
Weakness

CWE details

No CWE listed

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