Executive brief
A vulnerability in the Linux kernel's io_uring component could allow a local process to cause a system hang or performance degradation. The issue occurs because certain network polling tasks can run indefinitely without allowing other tasks to take over the processor. This could lead to kernel 'stuck task' errors and impact the overall availability of the system.
Technical details
A vulnerability in io_uring/napi.c exists where the busy_poll_to value is not capped. When NAPI is allowed to poll for events without a maximum time limit and no events are found, the loop fails to perform conditional rescheduling. This can lead to a task being identified as 'stuck' by the kernel because it occupies the CPU without yielding. The fix introduces a 10ms cap on the busy poll timeout to ensure the task eventually yields and prevents preemption complaints. This is primarily a local denial-of-service or system stability issue.
Affected products
- Linux Linux Kernel 6.9 to 7.1
Timeline
- 2026-06-26: disclosed
- 2026-06-26: advisory