Unity Linux 20.1050e Security Update: kernel (UTSA-2026-006830)

medium Nessus Plugin ID 305308

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-2026-006830 advisory.

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

netfilter: nft_set_pipapo: do not free live element

Pablo reports a crash with large batches of elements with a back-to-back add/remove pattern. Quoting Pablo:

add_elem(00000000) timeout 100 ms ...
add_elem(0000000X) timeout 100 ms del_elem(0000000X) <---------------- delete one that was just added ...
add_elem(00005000) timeout 100 ms

1) nft_pipapo_remove() removes element 0000000X Then, KASAN shows a splat.

Looking at the remove function there is a chance that we will drop a rule that maps to a non-deactivated element.

Removal happens in two steps, first we do a lookup for key k and return the to-be-removed element and mark it as inactive in the next generation.
Then, in a second step, the element gets removed from the set/map.

The _remove function does not work correctly if we have more than one element that share the same key.

This can happen if we insert an element into a set when the set already holds an element with same key, but the element mapping to the existing key has timed out or is not active in the next generation.

In such case its possible that removal will unmap the wrong element.
If this happens, we will leak the non-deactivated element, it becomes unreachable.

The element that got deactivated (and will be freed later) will remain reachable in the set data structure, this can result in a crash when such an element is retrieved during lookup (stale pointer).

Add a check that the fully matching key does in fact map to the element that we have marked as inactive in the deactivation step.
If not, we need to continue searching.

Add a bug/warn trap at the end of the function as well, the remove function must not ever be called with an invisible/unreachable/non-existent element.

v2: avoid uneeded temporary variable (Stefano)

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?f5b0d5da

http://www.nessus.org/u?0446063d

https://nvd.nist.gov/vuln/detail/CVE-2024-26924

Plugin Details

Severity: Medium

ID: 305308

File Name: unity_linux_UTSA-2026-006830.nasl

Version: 1.1

Type: Local

Published: 4/8/2026

Updated: 4/8/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 4.8

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

CVSS Score Source: CVE-2024-26924

CVSS v3

Risk Factor: Medium

Base Score: 5.9

Temporal Score: 5.2

Vector: CVSS:3.0/AV:N/AC:H/PR:N/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/cpu, Host/UOS-Server/release, Host/UOS-Server/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 4/8/2026

Vulnerability Publication Date: 4/24/2024

Reference Information

CVE: CVE-2024-26924