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Unity Linux 20.1070e Security Update: python-filelock (UTSA-2026-099470)

medium Nessus Plugin ID 336866

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-2026-099470 advisory.

 filelock is a platform-independent file lock for Python. In versions prior to 3.20.1, a Time-of-Check- Time-of-Use (TOCTOU) race condition allows local attackers to corrupt or truncate arbitrary user files through symlink attacks. The vulnerability exists in both Unix and Windows lock file creation where filelock checks if a file exists before opening it with O_TRUNC. An attacker can create a symlink pointing to a victim file in the time gap between the check and open, causing os.open() to follow the symlink and truncate the target file. All users of filelock on Unix, Linux, macOS, and Windows systems are impacted.
 The vulnerability cascades to dependent libraries. The attack requires local filesystem access and ability to create symlinks (standard user permissions on Unix; Developer Mode on Windows 10+). Exploitation succeeds within 1-3 attempts when lock file paths are predictable. The issue is fixed in version 3.20.1.
 If immediate upgrade is not possible, use SoftFileLock instead of UnixFileLock/WindowsFileLock (note:
 different locking semantics, may not be suitable for all use cases); ensure lock file directories have restrictive permissions (chmod 0700) to prevent untrusted users from creating symlinks; and/or monitor lock file directories for suspicious symlinks before running trusted applications. These workarounds provide only partial mitigation. The race condition remains exploitable. Upgrading to version 3.20.1 is strongly recommended.

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 python-filelock package.

See Also

https://atomgit.com/src-openeuler/python-filelock/issues/16

https://nvd.nist.gov/vuln/detail/CVE-2025-68146

http://www.nessus.org/u?f09d4a12

Plugin Details

Severity: Medium

ID: 336866

File Name: unity_linux_UTSA-2026-099470.nasl

Version: 1.1

Type: Local

Published: 8/17/2026

Updated: 8/17/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.5

Percentile: 57.51

CVSS v2

Risk Factor: Medium

Base Score: 5.7

Temporal Score: 4.5

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

CVSS Score Source: CVE-2025-68146

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 5.9

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

Temporal Vector: CVSS:3.0/E:P/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 Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 8/10/2026

Vulnerability Publication Date: 12/16/2025

Reference Information

CVE: CVE-2025-68146