# CVE-2026-103672: HMS Networks PEAK-System PCAN buffer overflow in DLC parser

Source: https://junglewise.ai/threats/cve-2026-103672-the-peak-system-pcan-parser-indexes-a-length-table-using  
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-2026-103672 · Severity: high · CVSS 7.1 · Published 2026-10-20

HMS Networks PEAK-System PCAN is a Windows driver for CAN bus communication in industrial and transportation systems. The driver contains a buffer overflow vulnerability in its parser that fails to validate the Data Length Code (DLC) field, allowing an attacker to crash the Windows kernel or potentially execute code by crafting malicious CAN messages.

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-2026-103672 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-103672 being exploited in the wild.

**How severe is CVE-2026-103672?** High severity, with a CVSS score of 7.1, 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-2026-103672?** Yes: fixed in HMS Networks 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-2026-103672 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-103672?** 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 HMS Networks PEAK-System Device Driver Setup 5.1.4; PCAN Windows CAN device drivers 5.1.4

## Technical details

The PCAN parser uses an attacker-controlled DLC value to index a length table without enforcing the valid range (DLC ≤ 0x0f), then performs an unchecked copy of attacker payload from a fixed offset into a fixed-size stack buffer. This is a classic out-of-bounds write vulnerability reachable via the file-device write path with low privilege, leading to kernel crash.

## 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 diagnostic call](https://junglewise.ai/threats/cve-2026-101103-the-peak-system-pcan-diagnostic-call-did-not-validate-that-the)