CVE-2025-39724 Affecting kernel-uek package, versions <0:5.4.17-2136.348.3.el8uek


Severity

Recommended
high

Based on Oracle Linux security rating.

Threat Intelligence

EPSS
0.03% (9th percentile)

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  • Snyk IDSNYK-ORACLE8-KERNELUEK-13540491
  • published13 Oct 2025
  • disclosed5 Sept 2025

Introduced: 5 Sep 2025

CVE-2025-39724  (opens in a new tab)

How to fix?

Upgrade Oracle:8 kernel-uek to version 0:5.4.17-2136.348.3.el8uek or higher.
This issue was patched in ELSA-2025-20663.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-uek package and not the kernel-uek package as distributed by Oracle. See How to fix? for Oracle:8 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

serial: 8250: fix panic due to PSLVERR

When the PSLVERR_RESP_EN parameter is set to 1, the device generates an error response if an attempt is made to read an empty RBR (Receive Buffer Register) while the FIFO is enabled.

In serial8250_do_startup(), calling serial_port_out(port, UART_LCR, UART_LCR_WLEN8) triggers dw8250_check_lcr(), which invokes dw8250_force_idle() and serial8250_clear_and_reinit_fifos(). The latter function enables the FIFO via serial_out(p, UART_FCR, p->fcr). Execution proceeds to the serial_port_in(port, UART_RX). This satisfies the PSLVERR trigger condition.

When another CPU (e.g., using printk()) is accessing the UART (UART is busy), the current CPU fails the check (value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR) in dw8250_check_lcr(), causing it to enter dw8250_force_idle().

Put serial_port_out(port, UART_LCR, UART_LCR_WLEN8) under the port->lock to fix this issue.

Panic backtrace: [ 0.442336] Oops - unknown exception [#1] [ 0.442343] epc : dw8250_serial_in32+0x1e/0x4a [ 0.442351] ra : serial8250_do_startup+0x2c8/0x88e ... [ 0.442416] console_on_rootfs+0x26/0x70

CVSS Base Scores

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