CVE-2026-99229
Description
A flaw was found in the Linux kernel's io_uring subsystem. A local attacker can cause a Denial of Service (DoS) by triggering an infinite loop when waiting for completion queue events. If entries on the overflow list cannot be flushed into the completion queue, the waiting kernel task continuously spins without processing signals or timeouts, resulting in an unkillable process that monopolizes system resources.
Statement
This vulnerability is rated Moderate rather than Important because exploitation requires local access and can only result in a denial of service condition without compromising data confidentiality or system integrity. An authenticated local user must be able to interact with the kernel's asynchronous I/O framework and create specialized completion queue configurations to trigger the hang. In enterprise installations where io_uring is restricted or not utilized by unprivileged accounts, exposure is significantly reduced. Because the spin condition prevents the affected task from receiving termination signals, the impact is confined to CPU consumption by the stuck process unless system resources become exhausted.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Amplification
An infinite loop will cause unexpected consumption of resources, such as CPU cycles or memory. The software's operation may slow down, or cause a long time to respond.
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