CVE-2026-64528
Received Received - Intake

Deadlock in Linux Kernel Serial Driver

Vulnerability report for CVE-2026-64528, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-07-25

Last updated on: 2026-07-25

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: tty: serial: samsung: Remove redundant port lock acquisition in rx helpers Sashiko identified a deadlock when the console flow is engaged [1]. When console flow control is enabled (UPF_CONS_FLOW), s3c24xx_serial_stop_tx() calls s3c24xx_serial_rx_enable() and s3c24xx_serial_start_tx() calls s3c24xx_serial_rx_disable(). The serial core framework invokes the .stop_tx() and .start_tx() callbacks with the port->lock spinlock already held. Furthermore, all internal driver paths that invoke stop_tx (such as the DMA TX completion handler s3c24xx_serial_tx_dma_complete() or the PIO TX IRQ handler s3c24xx_serial_tx_irq()) also acquire port->lock prior to calling it. (Note that s3c24xx_serial_start_tx() is only invoked by the serial core). However, s3c24xx_serial_rx_enable() and s3c24xx_serial_rx_disable() unconditionally attempt to acquire port->lock again using uart_port_lock_irqsave(). Since spinlocks are not recursive, this causes a deadlock on the same CPU when console flow control is engaged. Remove the redundant lock acquisition from both rx helper functions.

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Meta Information

Published
2026-07-25
Last Modified
2026-07-25
Generated
2026-07-25
AI Q&A
2026-07-25
EPSS Evaluated
N/A
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 is a deadlock vulnerability in the Linux kernel's serial driver for Samsung devices. When console flow control is enabled, the driver's transmit functions call receive helper functions that attempt to reacquire a lock already held, causing a system hang.

Detection Guidance

This vulnerability is specific to the Linux kernel's serial driver (samsung) and may not have direct network detection methods. Check kernel logs for deadlock warnings or system hangs related to serial console operations. Commands like 'dmesg | grep -i deadlock' or 'journalctl -k | grep -i serial' may help identify issues.

Impact Analysis

The deadlock can freeze the system when console flow control is active, potentially leading to unresponsive input/output, system hangs, or requiring a reboot to recover.

Mitigation Strategies

Apply the Linux kernel patch that resolves this issue. Update to a kernel version containing the fix for the samsung serial driver deadlock. If console flow control is not required, consider disabling it as a temporary workaround.

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