Medium [CVE-2026-53321] cap busy_poll_to 10 msec
This medium-severity Red Hat Linux advisory covers CVE-2026-53321 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat package: kernel-rt.
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Summary
In the Linux kernel, the following vulnerability has been resolved: io_uring/napi: cap busy_poll_to 10 msec Currently there's no cap on the maximum amount of time that napi is allowed to poll if no events are found, which can lead to kernel complaints on a task being stuck as there's no conditional rescheduling done within that loop.
Just cap it to 10 msec in total, that's already way above any kind of sane value that will reap any benefits, yet low enough that it's nowhere near being able to trigger preemption complaints. A flaw was found in the Linux kernel's io_uring subsystem, specifically in the Networked Asynchronous Packet Interface (NAPI) busy polling.
This vulnerability allows NAPI to poll indefinitely for events when none are present, which can cause a task to become stuck. This can lead to a Denial of Service (DoS) condition, making the system unresponsive.
The issue is addressed by implementing a 10-millisecond cap on the busy polling duration. Red Hat severity: Moderate — CVSS 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).
Weakness: CWE-835. Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 9.
Red Hat does not currently list a fixing RHSA for this CVE.
Affected products named by the advisory: Red Hat package: kernel-rt.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · medium-confidence parse· fetched 8 days ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · medium-confidence parse· fetched 8 days ago·verify at source
Mitigation
The source record does not include mitigation steps. That is not a statement that no fix exists — read the vendor advisory below for the authoritative guidance.
Official advisory · medium-confidence parse· fetched 8 days ago·verify at source
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