Executive Summary

CVE-2025-41259 is a privilege escalation vulnerability in SWUpdate versions before 2026.05 caused by a time-of-check time-of-use (TOCTOU) race condition.

The vulnerability arises because SWUpdate uses the /tmp directory for temporary files, which has a sticky bit allowing users to control their own directories.

An attacker can pre-create a scripts folder in /tmp with controlled permissions and then replace legitimate script files during the update process before SWUpdate executes them.

Since SWUpdate runs as root, this allows local unprivileged attackers to execute untrusted scripts or escalate their privileges to root by manipulating signed update files.

The issue was fixed in version 2026.05 by the vendor.

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Impact Analysis

This vulnerability can allow a local unprivileged attacker to escalate their privileges to root on the affected system.

By exploiting the TOCTOU race condition, an attacker can execute arbitrary code with root privileges by injecting untrusted scripts during the update process.

This can lead to full system compromise, unauthorized installation of malicious content, and loss of system integrity.

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Detection Guidance

This vulnerability arises from a TOCTOU race condition in SWUpdate versions before 2026.05, specifically related to the use of the /tmp directory for temporary files. Detection involves checking if your system is running a vulnerable version of SWUpdate and monitoring for suspicious activity involving the /tmp/scripts directory or unexpected script replacements during update processes.

You can detect the vulnerability by verifying the SWUpdate version installed on your system:

• swupdate --version

If the version is before 2026.05, your system is vulnerable.

Additionally, you can check for suspicious directories or files in /tmp that could be exploited:

• ls -ld /tmp/scripts
• find /tmp -user <unprivileged_user> -type d -name scripts

Monitoring logs for unexpected script execution or changes during update operations may also help detect exploitation attempts.

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Mitigation Strategies

The primary mitigation is to update SWUpdate to version 2026.05 or later, where the vulnerability has been fixed.

Additional immediate steps include:

• Configure SWUpdate to use a restrictive temporary directory instead of /tmp, or use randomly named temporary folders to prevent attackers from pre-creating malicious directories.
• Minimize the time between integrity checks and installation during the update process to reduce the window for race conditions.
• Monitor and restrict permissions on the /tmp directory to prevent unprivileged users from creating or modifying scripts folders used by SWUpdate.

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Compliance Impact

The vulnerability in SWUpdate allows local unprivileged attackers to escalate privileges to root or install untrusted contents using a signed update due to a TOCTOU race condition. This could lead to unauthorized code execution and potential compromise of system integrity.

Such a security flaw may impact compliance with standards and regulations like GDPR and HIPAA, which require maintaining the confidentiality, integrity, and availability of systems and data. If exploited, this vulnerability could lead to unauthorized access or modification of sensitive data, thereby violating these compliance requirements.

Organizations using affected versions of SWUpdate should apply the vendor fix (version 2026.05 or later) and implement recommended mitigations to reduce the risk of exploitation and maintain compliance.

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