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Unity Linux 20.1070e Security Update: kernel (UTSA-2026-013212)

medium Nessus Plugin ID 308086

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-2026-013212 advisory.

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

 nbd: fix incomplete validation of ioctl arg

 We tested and found an alarm caused by nbd_ioctl arg without verification.
 The UBSAN warning calltrace like below:

 UBSAN: Undefined behaviour in fs/buffer.c:1709:35 signed integer overflow:
 -9223372036854775808 - 1 cannot be represented in type 'long long int' CPU: 3 PID: 2523 Comm: syz-executor.0 Not tainted 4.19.90 #1 Hardware name: linux,dummy-virt (DT) Call trace:
 dump_backtrace+0x0/0x3f0 arch/arm64/kernel/time.c:78 show_stack+0x28/0x38 arch/arm64/kernel/traps.c:158
 __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x170/0x1dc lib/dump_stack.c:118 ubsan_epilogue+0x18/0xb4 lib/ubsan.c:161 handle_overflow+0x188/0x1dc lib/ubsan.c:192
 __ubsan_handle_sub_overflow+0x34/0x44 lib/ubsan.c:206
 __block_write_full_page+0x94c/0xa20 fs/buffer.c:1709 block_write_full_page+0x1f0/0x280 fs/buffer.c:2934 blkdev_writepage+0x34/0x40 fs/block_dev.c:607
 __writepage+0x68/0xe8 mm/page-writeback.c:2305 write_cache_pages+0x44c/0xc70 mm/page-writeback.c:2240 generic_writepages+0xdc/0x148 mm/page-writeback.c:2329 blkdev_writepages+0x2c/0x38 fs/block_dev.c:2114 do_writepages+0xd4/0x250 mm/page-writeback.c:2344

 The reason for triggering this warning is __block_write_full_page()
 -> i_size_read(inode) - 1 overflow.
 inode->i_size is assigned in __nbd_ioctl() -> nbd_set_size() -> bytesize.
 We think it is necessary to limit the size of arg to prevent errors.

 Moreover, __nbd_ioctl() -> nbd_add_socket(), arg will be cast to int.
 Assuming the value of arg is 0x80000000000000001) (on a 64-bit machine), it will become 1 after the coercion, which will return unexpected results.

 Fix it by adding checks to prevent passing in too large numbers.

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?2bdcd242

http://www.nessus.org/u?65a97700

https://nvd.nist.gov/vuln/detail/CVE-2023-53513

Plugin Details

Severity: Medium

ID: 308086

File Name: unity_linux_UTSA-2026-013212.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-2023-53513

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: 4/21/2026

Vulnerability Publication Date: 6/27/2023

Reference Information

CVE: CVE-2023-53513