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Unity Linux 20.1070a Security Update: kernel (UTSA-2026-012994)

medium Nessus Plugin ID 307709

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-2026-012994 advisory.

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

 net: netpoll: fix incorrect refcount handling causing incorrect cleanup

 commit efa95b01da18 (netpoll: fix use after free) incorrectly ignored the refcount and prematurely set dev->npinfo to NULL during netpoll cleanup, leading to improper behavior and memory leaks.

 Scenario causing lack of proper cleanup:

 1) A netpoll is associated with a NIC (e.g., eth0) and netdev->npinfo is allocated, and refcnt = 1
 - Keep in mind that npinfo is shared among all netpoll instances. In this case, there is just one.

 2) Another netpoll is also associated with the same NIC and npinfo->refcnt += 1.
 - Now dev->npinfo->refcnt = 2;
 - There is just one npinfo associated to the netdev.

 3) When the first netpolls goes to clean up:
 - The first cleanup succeeds and clears np->dev->npinfo, ignoring refcnt.
 - It basically calls `RCU_INIT_POINTER(np->dev->npinfo, NULL);`
 - Set dev->npinfo = NULL, without proper cleanup
 - No ->ndo_netpoll_cleanup() is either called

 4) Now the second target tries to clean up
 - The second cleanup fails because np->dev->npinfo is already NULL.
 * In this case, ops->ndo_netpoll_cleanup() was never called, and the skb pool is not cleaned as well (for the second netpoll instance)
 - This leaks npinfo and skbpool skbs, which is clearly reported by kmemleak.

 Revert commit efa95b01da18 (netpoll: fix use after free) and adds clarifying comments emphasizing that npinfo cleanup should only happen once the refcount reaches zero, ensuring stable and correct netpoll behavior.

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?3d64ef07

http://www.nessus.org/u?2bc3114a

https://nvd.nist.gov/vuln/detail/CVE-2025-68245

Plugin Details

Severity: Medium

ID: 307709

File Name: unity_linux_UTSA-2026-012994.nasl

Version: 1.1

Type: Local

Published: 4/21/2026

Updated: 4/21/2026

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-2025-68245

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: 4/21/2026

Vulnerability Publication Date: 12/9/2025

Reference Information

CVE: CVE-2025-68245