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Unity Linux 20.1070e Security Update: kernel (UTSA-2025-986944)

medium Nessus Plugin ID 268679

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-2025-986944 advisory.

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

 net: hamradio: fix memory leak in mkiss_close

 My local syzbot instance hit memory leak in mkiss_open()[1]. The problem was in missing free_netdev() in mkiss_close().

 In mkiss_open() netdevice is allocated and then registered, but in mkiss_close() netdevice was only unregistered, but not freed.

 Fail log:

 BUG: memory leak unreferenced object 0xffff8880281ba000 (size 4096):
 comm syz-executor.1, pid 11443, jiffies 4295046091 (age 17.660s) hex dump (first 32 bytes):
 61 78 30 00 00 00 00 00 00 00 00 00 00 00 00 00 ax0.............
 00 27 fa 2a 80 88 ff ff 00 00 00 00 00 00 00 00 .'.*............
 backtrace:
 [<ffffffff81a27201>] kvmalloc_node+0x61/0xf0 [<ffffffff8706e7e8>] alloc_netdev_mqs+0x98/0xe80 [<ffffffff84e64192>] mkiss_open+0xb2/0x6f0 [1] [<ffffffff842355db>] tty_ldisc_open+0x9b/0x110 [<ffffffff84236488>] tty_set_ldisc+0x2e8/0x670 [<ffffffff8421f7f3>] tty_ioctl+0xda3/0x1440 [<ffffffff81c9f273>] __x64_sys_ioctl+0x193/0x200 [<ffffffff8911263a>] do_syscall_64+0x3a/0xb0 [<ffffffff89200068>] entry_SYSCALL_64_after_hwframe+0x44/0xae

 BUG: memory leak unreferenced object 0xffff8880141a9a00 (size 96):
 comm syz-executor.1, pid 11443, jiffies 4295046091 (age 17.660s) hex dump (first 32 bytes):
 e8 a2 1b 28 80 88 ff ff e8 a2 1b 28 80 88 ff ff ...(.......(....
 98 92 9c aa b0 40 02 00 00 00 00 00 00 00 00 00 .....@..........
 backtrace:
 [<ffffffff8709f68b>] __hw_addr_create_ex+0x5b/0x310 [<ffffffff8709fb38>] __hw_addr_add_ex+0x1f8/0x2b0 [<ffffffff870a0c7b>] dev_addr_init+0x10b/0x1f0 [<ffffffff8706e88b>] alloc_netdev_mqs+0x13b/0xe80 [<ffffffff84e64192>] mkiss_open+0xb2/0x6f0 [1] [<ffffffff842355db>] tty_ldisc_open+0x9b/0x110 [<ffffffff84236488>] tty_set_ldisc+0x2e8/0x670 [<ffffffff8421f7f3>] tty_ioctl+0xda3/0x1440 [<ffffffff81c9f273>] __x64_sys_ioctl+0x193/0x200 [<ffffffff8911263a>] do_syscall_64+0x3a/0xb0 [<ffffffff89200068>] entry_SYSCALL_64_after_hwframe+0x44/0xae

 BUG: memory leak unreferenced object 0xffff8880219bfc00 (size 512):
 comm syz-executor.1, pid 11443, jiffies 4295046091 (age 17.660s) hex dump (first 32 bytes):
 00 a0 1b 28 80 88 ff ff 80 8f b1 8d ff ff ff ff ...(............
 80 8f b1 8d ff ff ff ff 00 00 00 00 00 00 00 00 ................
 backtrace:
 [<ffffffff81a27201>] kvmalloc_node+0x61/0xf0 [<ffffffff8706eec7>] alloc_netdev_mqs+0x777/0xe80 [<ffffffff84e64192>] mkiss_open+0xb2/0x6f0 [1] [<ffffffff842355db>] tty_ldisc_open+0x9b/0x110 [<ffffffff84236488>] tty_set_ldisc+0x2e8/0x670 [<ffffffff8421f7f3>] tty_ioctl+0xda3/0x1440 [<ffffffff81c9f273>] __x64_sys_ioctl+0x193/0x200 [<ffffffff8911263a>] do_syscall_64+0x3a/0xb0 [<ffffffff89200068>] entry_SYSCALL_64_after_hwframe+0x44/0xae

 BUG: memory leak unreferenced object 0xffff888029b2b200 (size 256):
 comm syz-executor.1, pid 11443, jiffies 4295046091 (age 17.660s) hex dump (first 32 bytes):
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
 backtrace:
 [<ffffffff81a27201>] kvmalloc_node+0x61/0xf0 [<ffffffff8706f062>] alloc_netdev_mqs+0x912/0xe80 [<ffffffff84e64192>] mkiss_open+0xb2/0x6f0 [1] [<ffffffff842355db>] tty_ldisc_open+0x9b/0x110 [<ffffffff84236488>] tty_set_ldisc+0x2e8/0x670 [<ffffffff8421f7f3>] tty_ioctl+0xda3/0x1440 [<ffffffff81c9f273>] __x64_sys_ioctl+0x193/0x200 [<ffffffff8911263a>] do_syscall_64+0x3a/0xb0 [<ffffffff89200068>] entry_SYSCALL_64_after_hwframe+0x44/0xae

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?5c1d1706

http://www.nessus.org/u?60c70135

https://nvd.nist.gov/vuln/detail/CVE-2021-47237

Plugin Details

Severity: Medium

ID: 268679

File Name: unity_linux_UTSA-2025-986944.nasl

Version: 1.2

Type: local

Published: 10/7/2025

Updated: 10/15/2025

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-2021-47237

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: 9/23/2025

Vulnerability Publication Date: 5/21/2024

Reference Information

CVE: CVE-2021-47237