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Unity Linux 20.1050e Security Update: kernel (UTSA-2026-006746)

medium Nessus Plugin ID 305322

Synopsis

The Unity Linux host is missing one or more security updates.

Description

The Unity Linux 20 host has a package installed that is affected by a vulnerability as referenced in the UTSA-2026-006746 advisory.

 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

Tenable has extracted the preceding description block directly from the Unity Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Update the affected kernel package.

See Also

http://www.nessus.org/u?8f69da4e

http://www.nessus.org/u?f6f76f76

https://nvd.nist.gov/vuln/detail/CVE-2025-39724

Plugin Details

Severity: Medium

ID: 305322

File Name: unity_linux_UTSA-2026-006746.nasl

Version: 1.1

Type: Local

Published: 4/8/2026

Updated: 4/8/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.4

Vector: CVSS2#AV:L/AC:L/Au:S/C:N/I:N/A:C

CVSS Score Source: CVE-2025-39724

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 4.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/UOS-Server/release, Host/UOS-Server/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 4/8/2026

Vulnerability Publication Date: 6/10/2025

Reference Information

CVE: CVE-2025-39724