# CVE-2026-68449: ata: sata_dwc_460ex: fix infinite loop in NCQ tag completion bit-scanning

> A local attacker can trigger an infinite loop in the SATA DWC driver, causing a system hang or crash.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 12 Aug 2026
- **Updated:** 19 Aug 2026
- **Also known as:** BELL-CVE-2026-68449, DEBIAN-CVE-2026-68449, GHSA-vjpx-hgc2-722c, UBUNTU-CVE-2026-68449

## What is CVE-2026-68449?

CVE-2026-68449 is a denial of service vulnerability in Linux, published on 12 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

## Which versions are affected by CVE-2026-68449?


## How do I fix CVE-2026-68449?

Apply the vendor's patch.

## Is CVE-2026-68449 being exploited?

There is no known exploitation of CVE-2026-68449 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68449 and fix it if it is affected.

What it is: CVE-2026-68449 is a denial of service vulnerability in Linux, published on 12 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-68449 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-68449/ (Markdown: https://insights.sbomify.com/CVE-2026-68449/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68449
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68449
- OSV: https://osv.dev/vulnerability/CVE-2026-68449

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68449/
Summaries are generated and may contain mistakes; the official description above is the record.