Unity Linux 20.1050a Security Update: kernel (UTSA-2026-146676)

high Nessus Plugin ID 373100

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-2026-146676 advisory.

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

md: do overflow check for sb->bblog_shift in super_1_load()

In super_1_load(), sb->bblog_shift is an __u8 type value loaded from on- disk superblock. It is used for badblocks API badblocks_set() by the following sequence,

1930 rdev->badblocks.shift = sb->bblog_shift;
1931 for (i = 0 ; i < (sectors << (9-3)) ; i++, bbp++) { 1932 u64 bb = le64_to_cpu(*bbp);
1933 int count = bb & (0x3ff);
1934 u64 sector = bb >> 10;
1935 sector <<= sb->bblog_shift;
1936 count <<= sb->bblog_shift;
1937 if (bb + 1 == 0) 1938 break;
1939 if (!badblocks_set(&rdev->badblocks, sector, count, 1)) 1940 return -EINVAL;
1941 }

bb->bblog_shit is in range of 0-255, variable sector is 64bit width, for an invalid bb->bblog_shit, it is possible to make sector be overflowed by the following calculation, 1935 sector <<= sb->bblog_shift;
Then in turn when call badblocks_set() at line 1939 with the invalid rdev->badblocks.shift set at line 1930, may result an overflow inside
_badblocks_clear() in block/badblocks.c.

Although there are many places to call badblocks APIs, the non-zero shift value is only used in super_1_load(), other places always use 0 as the shift value. Therefore it is unnecessary to do a general shift value overflow check inside badblock API, and just check here as the caller.

This may avoid unnecessary check, make the badblocks API code more simple and elegant.

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.

Plugin Details

Severity: High

ID: 373100

File Name: unity_linux_UTSA-2026-146676.nasl

Version: 1.1

Type: Local

Family: Unity Linux Local Security Checks

Published: 10/28/2026

Updated: 10/28/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.27

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

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

CVSS Score Source: CVE-2026-89557

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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: 10/28/2026

Vulnerability Publication Date: 9/11/2026

Reference Information

CVE: CVE-2026-89557

Detections

Analytics