CVE-2026-93276
Received Received - Intake

USB2 Regulator State Handling Flaw in Renesas R-Car Gen3 PHY

Publication date: 2026-09-24

Last updated on: 2026-09-24

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: phy: renesas: phy-rcar-gen3-usb2: Fix devm action registration for disabled VBUS regulator devm_regulator_get_exclusive() initialises the regulator with enable_count = 1, requiring the consumer to disable it before release. The devm disable action was previously only registered when the caller explicitly requested enable, so when the regulator was left in its initial enabled state without an explicit enable call, the cleanup path skipped decrementing enable_count, triggering a WARN_ON during regulator release on device removal. Fix this by always registering the devm disable action based on the actual enabled state via regulator_is_enabled(), regardless of whether the caller requested an explicit enable. This covers both the explicitly enabled case and the initial state set by devm_regulator_get_exclusive().

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Meta Information

Published
2026-09-24
Last Modified
2026-09-24
Generated
2026-09-25
AI Q&A
2026-09-24
EPSS Evaluated
N/A
NVD
CVE-2026-93276
EUVD
EUVD-2026-86148

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
renesas phy-rcar-gen3-usb2 *

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves improper handling of a USB VBUS regulator in the Renesas R-Car Gen3 USB2 PHY driver. The issue occurs because devm_regulator_get_exclusive() initializes the regulator with enable_count set to 1, requiring explicit disable before release. The cleanup path failed to account for the regulator's initial enabled state, leading to a warning during device removal when enable_count was not decremented properly.

Detection Guidance

This vulnerability is specific to the Linux kernel's Renesas R-Car Gen3 USB2 PHY driver and does not have network-based detection methods. Check kernel logs for regulator-related warnings during device removal or USB subsystem errors. Commands: dmesg | grep -i regulator, dmesg | grep -i usb, journalctl -k | grep -i regulator.

Impact Analysis

This vulnerability could cause system instability or crashes when removing USB devices on systems using the affected Renesas R-Car Gen3 USB2 PHY driver. It may trigger kernel warnings or errors during device teardown, potentially affecting system reliability.

Compliance Impact

This vulnerability does not directly affect compliance with standards like GDPR or HIPAA. It is a Linux kernel driver issue related to regulator management in the Renesas R-Car Gen3 USB2 PHY, which could lead to system instability but does not involve data handling or privacy concerns.

Mitigation Strategies

Update the Linux kernel to a patched version that includes the fix for this issue. Monitor kernel updates from your distribution and apply them promptly. No immediate configuration changes are required beyond the kernel update.

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