Unity Linux 20.1050e Security Update: kernel (UTSA-2026-007488)

medium Nessus Plugin ID 307108

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-2026-007488 advisory.

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

ext4: refresh inline data size before write operations

The cached ei->i_inline_size can become stale between the initial size check and when ext4_update_inline_data()/ext4_create_inline_data() use it. Although ext4_get_max_inline_size() reads the correct value at the time of the check, concurrent xattr operations can modify i_inline_size before ext4_write_lock_xattr() is acquired.

This causes ext4_update_inline_data() and ext4_create_inline_data() to work with stale capacity values, leading to a BUG_ON() crash in ext4_write_inline_data():

kernel BUG at fs/ext4/inline.c:1331! BUG_ON(pos + len > EXT4_I(inode)->i_inline_size);

The race window:
1. ext4_get_max_inline_size() reads i_inline_size = 60 (correct) 2. Size check passes for 50-byte write 3. [Another thread adds xattr, i_inline_size changes to 40] 4. ext4_write_lock_xattr() acquires lock 5. ext4_update_inline_data() uses stale i_inline_size = 60 6. Attempts to write 50 bytes but only 40 bytes actually available 7. BUG_ON() triggers

Fix this by recalculating i_inline_size via ext4_find_inline_data_nolock() immediately after acquiring xattr_sem. This ensures ext4_update_inline_data() and ext4_create_inline_data() work with current values that are protected from concurrent modifications.

This is similar to commit a54c4613dac1 (ext4: fix race writing to an inline_data file while its xattrs are changing) which fixed i_inline_off staleness. This patch addresses the related i_inline_size staleness issue.

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?9a2b570e

http://www.nessus.org/u?b08726aa

https://nvd.nist.gov/vuln/detail/CVE-2025-68264

Plugin Details

Severity: Medium

ID: 307108

File Name: unity_linux_UTSA-2026-007488.nasl

Version: 1.1

Type: Local

Published: 4/17/2026

Updated: 4/17/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.0

CVSS v2

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 4.1

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

CVSS Score Source: CVE-2025-68264

CVSS v3

Risk Factor: Medium

Base Score: 6.3

Temporal Score: 5.5

Vector: CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:N/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/cpu, Host/UOS-Server/release, Host/UOS-Server/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 4/17/2026

Vulnerability Publication Date: 12/16/2025

Reference Information

CVE: CVE-2025-68264