CVE-2026-68092 time/jiffies: Register jiffies clocksource before usage
A Linux kernel bug causes boot delays in XEN HVMs by clamping time progress, resulting in a denial of service during system startup.
- 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-2026-68092?
CVE-2026-68092 is a denial of service vulnerability in Linux, published on 10 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:
time/jiffies: Register jiffies clocksource before usage
Teddy reported that a XEN HVM has a long boot delay, which was bisected to the recent enhancements to the negative motion detection. It turned out that the jiffies clocksource is used in early boot before it is registered, which leaves the max_delta_raw field at zero. That causes the read out to be clamped to the max delta of 0, which means time is not making progress.
Cure it by ensuring that it is initialized before its first usage in timekeeping_init().
Which versions are affected by CVE-2026-68092?
How do I fix CVE-2026-68092?
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-2026-68092 being exploited?
There is no known exploitation of CVE-2026-68092 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-68092, DEBIAN-CVE-2026-68092, GHSA-x4mh-q3jq-rwpp, UBUNTU-CVE-2026-68092.