Unity Linux 20.1070e Security Update: netty (UTSA-2026-017767)

medium Nessus Plugin ID 314067

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-2026-017767 advisory.

Netty is an open-source, asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. In Netty before version 4.1.59.Final there is a vulnerability on Unix-like systems involving an insecure temp file. When netty's multipart decoders are used local information disclosure can occur via the local system temporary directory if temporary storing uploads on the disk is enabled. On unix-like systems, the temporary directory is shared between all user.
As such, writing to this directory using APIs that do not explicitly set the file/directory permissions can lead to information disclosure. Of note, this does not impact modern MacOS Operating Systems. The method File.createTempFile on unix-like systems creates a random file, but, by default will create this file with the permissions -rw-r--r--. Thus, if sensitive information is written to this file, other local users can read this information. This is the case in netty's AbstractDiskHttpData is vulnerable.
This has been fixed in version 4.1.59.Final. As a workaround, one may specify your own java.io.tmpdir when you start the JVM or use DefaultHttpDataFactory.setBaseDir(...) to set the directory to something that is only readable by the current user.

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 netty package.

Plugin Details

Severity: Medium

ID: 314067

File Name: unity_linux_UTSA-2026-017767.nasl

Version: 1.1

Type: Local

Family: Unity Linux Local Security Checks

Published: 5/11/2026

Updated: 5/11/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Low

Base Score: 1.9

Temporal Score: 1.5

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

CVSS Score Source: CVE-2021-21290

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 5

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

Temporal Vector: CVSS:3.0/E:P/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 Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 5/11/2026

Vulnerability Publication Date: 2/8/2021

Reference Information

CVE: CVE-2021-21290

Detections

Analytics