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.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
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.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-68449 being exploited?
There is no known exploitation of CVE-2026-68449 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-68449, DEBIAN-CVE-2026-68449, GHSA-vjpx-hgc2-722c, UBUNTU-CVE-2026-68449.