Unity Linux 20.1050a Security Update: kernel (UTSA-2026-146624)

critical Nessus Plugin ID 373169

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-2026-146624 advisory.

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

net: skbuff: don't skb_tx_error() the source skb in skb_zerocopy()

skb_zerocopy() copies frags from @from into @to. On an skb_orphan_frags() failure it calls skb_tx_error(@from), a destructive operation on the source skb the copy helper does not own. That completes @from's zerocopy uarg and clears SKBFL_ALL_ZEROCOPY, including the SKBFL_SHARED_FRAG page-ownership marker.

Both callers already report the failure on their own drop path.
nfnetlink_queue does it at nla_put_failure, and Open vSwitch does it in the flow-miss drop arm of ovs_dp_process_packet(), so nothing is lost by dropping it here.

On Open vSwitch's OVS_ACTION_ATTR_USERSPACE path the skb is not freed on this error: do_execute_actions() ignores output_userspace()'s return value and, unless the upcall was the last action, keeps forwarding the same skb through the flow's remaining actions. The uarg is completed while that skb is still in flight, telling the producer its buffers are free, and SKBFL_SHARED_FRAG is cleared on an skb the rest of the stack still handles. That flag is what makes esp_input() call skb_cow_data() instead of decrypting in place, so a later local ESP delivery can decrypt over frags the skb does not own privately.

Leave error reporting to the callers.

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.

Plugin Details

Severity: Critical

ID: 373169

File Name: unity_linux_UTSA-2026-146624.nasl

Version: 1.1

Type: Local

Family: Unity Linux Local Security Checks

Published: 10/28/2026

Updated: 10/28/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5

Percentile: 92.99

CVSS v2

Risk Factor: High

Base Score: 7.2

Temporal Score: 5.3

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

CVSS Score Source: CVE-2026-90049

CVSS v3

Risk Factor: Critical

Base Score: 9.3

Temporal Score: 8.1

Vector: CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:C/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/UOS-Server/release, Host/UOS-Server/rpm-list, Host/cpu

Exploit Ease: No known exploits are available

Patch Publication Date: 10/28/2026

Vulnerability Publication Date: 9/16/2026

Reference Information

CVE: CVE-2026-90049

Detections

Analytics