Unity Linux 20.1050a Security Update: kernel (UTSA-2026-100559)

high Nessus Plugin ID 336154

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-2026-100559 advisory.

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

keys: Pin request_key_auth payload in instantiate paths

A: request_key() B: KEYCTL_INSTANTIATE_IOV ================ =========================

create auth key store rka in auth key wait for helper get auth key load rka from auth key copy user payload sleep on #PF

helper completed detach and free rka destroy auth key wake up use rka->target_key
**USE-AFTER-FREE**

Give request_key_auth payloads a refcount. Take a payload reference while authkey->sem stabilizes the payload and revocation state. Hold that reference across the instantiate and reject paths. Drop the auth key owning reference from revoke and destroy.

[jarkko: Replaced the first two paragraphs of text with an actual concurrency scenario.]

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

https://nvd.nist.gov/vuln/detail/CVE-2026-63823

http://www.nessus.org/u?6301bec5

http://www.nessus.org/u?66e3687b

Plugin Details

Severity: High

ID: 336154

File Name: unity_linux_UTSA-2026-100559.nasl

Version: 1.1

Type: Local

Published: 8/17/2026

Updated: 8/17/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.11

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

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

CVSS Score Source: CVE-2026-63823

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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: 8/13/2026

Vulnerability Publication Date: 7/8/2026

Reference Information

CVE: CVE-2026-63823