Executive Summary

CVE-2026-45250 is a stack buffer overflow vulnerability in FreeBSD's setcred(2) system call. The vulnerability arises because the system call copies a user-supplied list of supplementary groups into a fixed-size kernel stack buffer without first validating the length of that list.

Since the bounds check on the supplementary groups list occurs only after the buffer has been written, an unprivileged local user can trigger a stack buffer overflow by providing a list that exceeds the buffer's capacity.

This flaw allows an attacker to execute arbitrary code in the kernel context, potentially leading to privilege escalation.

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Compliance Impact

The provided information does not specify how this vulnerability impacts compliance with common standards and regulations such as GDPR or HIPAA.

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Impact Analysis

This vulnerability can allow an unprivileged local user to execute arbitrary code within the kernel, which can lead to gaining elevated privileges on the affected FreeBSD system.

Successful exploitation means an attacker could take full control of the system, bypassing normal security restrictions.

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Mitigation Strategies

To mitigate the CVE-2026-45250 vulnerability, users should upgrade their FreeBSD systems by applying the official patches released by the FreeBSD Project for stable and release branches.

• Use pkg or freebsd-update tools to install the patches.
• Alternatively, apply the source code patches provided by the FreeBSD Project.
• After patching, perform a system reboot to ensure the updates take effect.

No workaround is available, so timely patching and rebooting are critical.

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Detection Guidance

There is no specific detection method or commands provided in the available resources to identify exploitation or presence of this vulnerability on a system or network.

The vulnerability is a local kernel stack buffer overflow triggered by the setcred(2) system call when an unprivileged user supplies an excessively long list of supplementary groups.

Detection would typically involve monitoring for unusual kernel panics or crashes related to setcred(2), but no explicit detection commands or signatures are mentioned.

The recommended action is to apply the official patches released by the FreeBSD Project and reboot the system to mitigate the vulnerability.

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