CVE-2026-93219 clocksource/drivers/timer-sun4i: Advertise a real minimum delta
A flaw in the Linux kernel sun4i timer driver can cause a boot hang or denial of service due to incorrect minimum delta advertisement.
- 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-2026-93219?
CVE-2026-93219 is a denial of service vulnerability in Linux, published on 24 Sep 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:
clocksource/drivers/timer-sun4i: Advertise a real minimum delta
sun4i_clkevt_next_event() compensates for the timer stop/start synchronization delay by programming evt - TIMER_SYNC_TICKS into the hardware interval register. The clockevent device currently advertises TIMER_SYNC_TICKS as min_delta_ticks, so the clockevents core is allowed to call set_next_event() with evt == TIMER_SYNC_TICKS.
That programs a zero-tick interval. With oneshot/highres/nohz timer operation this can leave the next event stuck, which was observed as a boot hang on Allwinner D1 after the clockevents core started reusing forced minimum-delta events.
Advertise one extra tick instead, so the smallest event accepted by the core still programs at least one hardware tick after the synchronization compensation.
Which versions are affected by CVE-2026-93219?
How do I fix CVE-2026-93219?
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-2026-93219 being exploited?
There is no known exploitation of CVE-2026-93219 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-93219, DEBIAN-CVE-2026-93219, GHSA-7r67-4hf5-jfm4, UBUNTU-CVE-2026-93219.