# CVE-2026-101103: HMS Networks PEAK-System PCAN buffer overflow in diagnostic call

Source: https://junglewise.ai/threats/cve-2026-101103-the-peak-system-pcan-diagnostic-call-did-not-validate-that-the  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-20. Updated: 2026-10-20  
License: CC BY 4.0 with a link back

CVE-2026-101103 · Severity: medium · CVSS 5.5 · Published 2026-10-20

HMS Networks PEAK-System PCAN is a Windows driver for CAN bus communication used in industrial control systems. A buffer overflow vulnerability in a diagnostic function allows a privileged local attacker to crash the Windows kernel or potentially execute code, disrupting critical infrastructure including transportation, healthcare, energy, and manufacturing systems.

Technologies: [HMS Networks PCAN Windows CAN device drivers](https://junglewise.ai/threats/technologies/pcan-windows-can-device-drivers), [HMS Networks PEAK-System Device Driver Setup](https://junglewise.ai/threats/technologies/peak-system-device-driver-setup). Vendors: [HMS Networks](https://junglewise.ai/threats/vendors/hms-networks).

## Quick answers

**Is CVE-2026-101103 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-101103 being exploited in the wild.

**How severe is CVE-2026-101103?** Medium severity, with a CVSS score of 5.5, published 20 October 2026.

**Which products and versions are affected?** HMS Networks PCAN Windows CAN device drivers <=5.1.2; HMS Networks PEAK-System Device Driver Setup <=5.1.2.1151.

**Is there a fix for CVE-2026-101103?** Yes: fixed in PEAK-System Device Driver Setup 5.1.4, PCAN Windows CAN device drivers 5.1.4. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-101103 attacked?** It is attacked with local access, in device firmware.

**Am I affected by CVE-2026-101103?** Check whether you run HMS Networks PCAN Windows CAN device drivers or HMS Networks PEAK-System Device Driver Setup at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in PEAK-System Device Driver Setup 5.1.4, PCAN Windows CAN device drivers 5.1.4

## Technical details

The vulnerability is a classic buffer overflow (CWE-120) in the PCAN diagnostic call that fails to validate the caller-supplied output buffer size before writing the output record. A local attacker with privileges can provide an insufficiently sized output buffer, causing the driver to write beyond buffer boundaries. This requires local access and valid privileges but can result in kernel crash or code execution.

## Affected products

- HMS Networks PEAK-System Device Driver Setup <=5.1.2.1151
- HMS Networks PCAN Windows CAN device drivers <=5.1.2

## Timeline

- 2026-10-20: disclosed

## References

- [https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-293-01.json](https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-293-01.json)
- [https://www.cisa.gov/news-events/ics-advisories/icsa-26-293-01](https://www.cisa.gov/news-events/ics-advisories/icsa-26-293-01)

## Related threats

- [HMS Networks PEAK-System PCAN untrusted pointer dereference](https://junglewise.ai/threats/cve-2026-110322-the-peak-system-pcan-type-0x4030-processing-path-fails-to)
- [HMS Networks PEAK-System PCAN drivers kernel crash](https://junglewise.ai/threats/cve-2026-109576-hms-networks-peak-system-pcan-windows-drivers)
- [HMS Networks PEAK-System PCAN buffer overflow in driver](https://junglewise.ai/threats/cve-2026-105960-peak-system-pcan-contains-a-vulnerable-operation-involving-a)
- [HMS Networks PEAK-System PCAN buffer overflow in DLC parser](https://junglewise.ai/threats/cve-2026-103672-the-peak-system-pcan-parser-indexes-a-length-table-using)