CVE-2026-74754
Received Received - Intake

Race Condition in Linux Kernel SCSI Core Leads to Runtime PM Underflow

Vulnerability report for CVE-2026-74754, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-08-26

Last updated on: 2026-08-26

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: scsi: core: pair EH runtime PM get and put shost->eh_noresume is currently consulted twice in one error handling iteration: once before scsi_autopm_get_host() and once again before scsi_autopm_put_host(). That is racy when a PM-triggered error path flips shost->eh_noresume while the SCSI EH thread is still running. The problem flow looks like this: PM path ufshcd_set_dev_pwr_mode() shost->eh_noresume = 1 ufshcd_execute_start_stop <-- trigger EH ... shost->eh_noresume = 0 EH path scsi_error_handler() if (!shost->eh_noresume) scsi_autopm_get_host() <-- skipped ... if (!shost->eh_noresume) scsi_autopm_put_host() <-- executed later In that case one EH iteration can skip autoresume on entry and still drop a runtime PM reference on exit. That leaves an unmatched runtime PM put and can trigger a runtime PM usage count underflow. Fix this by making eh_noresume a regular bool so it can be accessed with READ_ONCE() and WRITE_ONCE(). Snapshot it once per EH iteration and use that snapshot for both runtime PM get and put decisions.

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Meta Information

Published
2026-08-26
Last Modified
2026-08-26
Generated
2026-09-15
AI Q&A
2026-08-26
EPSS Evaluated
2026-09-14
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

Helpful Resources

Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a race condition in the SCSI error handling (EH) and power management (PM) paths. The issue occurs when the PM path modifies a flag (shost->eh_noresume) while the EH thread is running, leading to mismatched runtime power management get and put operations. This can cause a runtime PM usage count underflow.

Detection Guidance

This vulnerability is specific to the Linux kernel's SCSI error handling and runtime power management. Detection requires checking kernel logs for SCSI error handler issues or runtime PM underflow warnings. Use commands like dmesg | grep -i 'scsi' or dmesg | grep -i 'runtime pm' to inspect for related errors.

Impact Analysis

This vulnerability may cause system instability or crashes due to runtime power management reference count underflows. It could lead to unexpected behavior in storage devices managed by the SCSI subsystem, potentially disrupting data access or system operations.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards as it pertains to a low-level Linux kernel runtime power management issue in the SCSI subsystem. Compliance impacts would only occur if exploitation led to system instability or data corruption, which is not described in the provided context.

Mitigation Strategies

Apply the kernel patch that fixes the eh_noresume race condition. Update to a Linux kernel version that includes the fix. Monitor SCSI device error handling logs for any remaining issues after patching.

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