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Unity Linux 20.1060e / 20.1070e Security Update: kernel (UTSA-2025-992645)

medium Nessus Plugin ID 280539

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-2025-992645 advisory.

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

 net: gso: fix ownership in __udp_gso_segment

 In __udp_gso_segment the skb destructor is removed before segmenting the skb but the socket reference is kept as-is. This is an issue if the original skb is later orphaned as we can hit the following bug:

 kernel BUG at ./include/linux/skbuff.h:3312! (skb_orphan) RIP: 0010:ip_rcv_core+0x8b2/0xca0 Call Trace:
 ip_rcv+0xab/0x6e0
 __netif_receive_skb_one_core+0x168/0x1b0 process_backlog+0x384/0x1100
 __napi_poll.constprop.0+0xa1/0x370 net_rx_action+0x925/0xe50

 The above can happen following a sequence of events when using OpenVSwitch, when an OVS_ACTION_ATTR_USERSPACE action precedes an OVS_ACTION_ATTR_OUTPUT action:

 1. OVS_ACTION_ATTR_USERSPACE is handled (in do_execute_actions): the skb goes through queue_gso_packets and then __udp_gso_segment, where its destructor is removed.
 2. The segments' data are copied and sent to userspace.
 3. OVS_ACTION_ATTR_OUTPUT is handled (in do_execute_actions) and the same original skb is sent to its path.
 4. If it later hits skb_orphan, we hit the bug.

 Fix this by also removing the reference to the socket in
 __udp_gso_segment.

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?464ec84e

http://www.nessus.org/u?ab64d61a

https://nvd.nist.gov/vuln/detail/CVE-2025-21926

Plugin Details

Severity: Medium

ID: 280539

File Name: unity_linux_UTSA-2025-992645.nasl

Version: 1.1

Type: local

Published: 12/30/2025

Updated: 12/30/2025

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-2025-21926

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/UOS-Server/release, Host/UOS-Server/rpm-list, Host/cpu

Exploit Ease: No known exploits are available

Patch Publication Date: 12/30/2025

Vulnerability Publication Date: 4/1/2025

Reference Information

CVE: CVE-2025-21926