CVE-2022-50552

Description

A use-after-free flaw was found in the Linux kernel block multiqueue request path during an elevator (scheduler) switch. When hardware queues are reinitialized, queue work can still run and grab a scheduler pointer that is being torn down. A local user could use this flaw to crash the system during heavy storage activity or device reset, resulting in a denial of service.

Statement

The race occurs because freezing a queue only blocks new request allocation and does not quiesce per-queue work. While the scheduler is being switched, pending run work may dereference a scheduler structure that is in teardown. The fix uses a quiesced switch so queue work cannot observe a half-torn-down scheduler.

Mitigation

To mitigate this issue, prevent module kyber-iosched from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.

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 HatNVDcve.org
Base Score5.37.8N/A
Attack VectorLocalLocalN/A
Attack ComplexityHighLowN/A
Privileges RequiredLowLowN/A
User InteractionNoneNoneN/A
ScopeUnchangedUnchangedN/A
ConfidentialityLowHighN/A
Integrity ImpactNoneHighN/A
Availability ImpactHighHighN/A

Vector

Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:H

NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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