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Unity Linux 20.1050e Security Update: kernel (UTSA-2026-102003)

medium Nessus Plugin ID 337330

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-2026-102003 advisory.

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

 xfrm: always flush state and policy upon NETDEV_UNREGISTER event

 syzbot is reporting that struct xfrm_state refcount is leaking.

 unregister_netdevice: waiting for netdevsim0 to become free. Usage count = 2 ref_tracker: netdev@ffff888052f24618 has 1/1 users at
 __netdev_tracker_alloc include/linux/netdevice.h:4400 [inline] netdev_tracker_alloc include/linux/netdevice.h:4412 [inline] xfrm_dev_state_add+0x3a5/0x1080 net/xfrm/xfrm_device.c:316 xfrm_state_construct net/xfrm/xfrm_user.c:986 [inline] xfrm_add_sa+0x34ff/0x5fa0 net/xfrm/xfrm_user.c:1022 xfrm_user_rcv_msg+0x58e/0xc00 net/xfrm/xfrm_user.c:3507 netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2550 xfrm_netlink_rcv+0x71/0x90 net/xfrm/xfrm_user.c:3529 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 ____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592
 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2646
 __sys_sendmsg+0x16d/0x220 net/socket.c:2678 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f

 This is because commit d77e38e612a0 (xfrm: Add an IPsec hardware offloading API) implemented xfrm_dev_unregister() as no-op despite xfrm_dev_state_add() from xfrm_state_construct() acquires a reference to struct net_device.
 I guess that that commit expected that NETDEV_DOWN event is fired before NETDEV_UNREGISTER event fires, and also assumed that xfrm_dev_state_add() is called only if (dev->features & NETIF_F_HW_ESP) != 0.

 Sabrina Dubroca identified steps to reproduce the same symptoms as below.

 echo 0 > /sys/bus/netdevsim/new_device dev=$(ls -1 /sys/bus/netdevsim/devices/netdevsim0/net/) ip xfrm state add src 192.168.13.1 dst 192.168.13.2 proto esp spi 0x1000 mode tunnel aead 'rfc4106(gcm(aes))' $key 128 offload crypto dev $dev dir out ethtool -K $dev esp-hw-offload off echo 0 > /sys/bus/netdevsim/del_device

 Like these steps indicate, the NETIF_F_HW_ESP bit can be cleared after xfrm_dev_state_add() acquired a reference to struct net_device.
 Also, xfrm_dev_state_add() does not check for the NETIF_F_HW_ESP bit when acquiring a reference to struct net_device.

 Commit 03891f820c21 (xfrm: handle NETDEV_UNREGISTER for xfrm device) re-introduced the NETDEV_UNREGISTER event to xfrm_dev_event(), but that commit for unknown reason chose to share xfrm_dev_down() between the NETDEV_DOWN event and the NETDEV_UNREGISTER event.
 I guess that that commit missed the behavior in the previous paragraph.

 Therefore, we need to re-introduce xfrm_dev_unregister() in order to release the reference to struct net_device by unconditionally flushing state and policy.

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-2026-43167

http://www.nessus.org/u?1beed84f

http://www.nessus.org/u?37d7fa94

Plugin Details

Severity: Medium

ID: 337330

File Name: unity_linux_UTSA-2026-102003.nasl

Version: 1.1

Type: Local

Published: 8/18/2026

Updated: 8/18/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5

Percentile: 93.96

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-2026-43167

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

Exploit Ease: No known exploits are available

Patch Publication Date: 8/17/2026

Vulnerability Publication Date: 4/7/2026

Reference Information

CVE: CVE-2026-43167