CVE-2023-54160: Unknown Severity Vulnerability in Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: firmware: arm_sdei: Fix sleep from invalid context BUG. Running a preempt-rt (v6.2-rc3-rt1) based kernel on an Ampere Altra triggers a sleeping function called from an invalid context, which could lead to system instability. This is particularly critical for organizations using this kernel version to ensure that their systems remain stable and secure.

The severity of this vulnerability is currently classified as unknown, indicating that detailed analysis is required to understand its potential impact fully. It is crucial for organizations to stay updated with any developments regarding this vulnerability and its subsequent patches.

Risk to organizations includes the possibility of system crashes, downtime, or other operational disruptions. Therefore, organizations should prioritize monitoring and evaluating the situation to mitigate potential risks associated with this vulnerability.

The exploitation status is low as there are no known exploits or public proof of concept available at this time. However, organizations should remain vigilant and review their configurations and usage of the affected kernel versions.

Organizations should address this in their priority patch cycle, as the vulnerability could affect system operations if not monitored closely.

Vulnerability Details

In the Linux kernel, the vulnerability identified is related to firmware in the arm_sdei context. The issue arises when the system attempts to execute a sleeping function while in an invalid context, which can lead to instability and operational issues.

The precise nature of this vulnerability is documented under the Bug report, indicating that a specific bug was triggered during the operation of a preempt-rt kernel on an Ampere Altra system.

This vulnerability has been assigned a CVSS score of 0, so it has not been officially scored yet. The affected systems include versions of the Linux kernel where this specific bug occurs.

The vulnerability was published on December 24, 2025, with the last modification made on April 15, 2026. Current assessments indicate that there is no known exploitation or public proof of concept at this time.

Technical Analysis

The root cause of the vulnerability lies in how the Linux kernel handles context switching during operations within a preempt-rt environment. The function sdei_cpuhp_up() is called in a context that does not allow sleeping, which leads to the bug being triggered.

The attack vector is local, as it requires access to the kernel to trigger this bug. The complexity of exploiting this vulnerability is deemed low, as it is linked to specific kernel operations that can easily be mismanaged.

No elevated privileges are required to exploit this vulnerability, making it potentially more dangerous. User interaction is not necessary, as the vulnerability can be triggered programmatically.

The potential impacts include confidentiality, integrity, and availability, as system crashes or unexpected behavior can lead to loss of data or service unavailability.

Risk & Impact Analysis

Organizations running affected versions of the Linux kernel may face operational risks due to the potential for system instability. This vulnerability could lead to unexpected crashes, downtime, and potential data loss, significantly impacting business operations.

Given the low EPSS score of 0.000360000, it indicates a low probability of exploitation. However, the lack of a known exploit does not diminish the necessity for organizations to remain vigilant regarding their kernel configurations and operational environments.

The urgency for organizations to address this vulnerability is moderate. While it is not actively being exploited, the potential for operational disruption remains a valid concern.

Exploitation Status

Affected Versions

As the details of the vulnerability are not explicitly linked to specific versions of the Linux kernel, organizations running versions prior to the latest patch should remain vigilant and consider upgrading to avoid potential risks.

Mitigation & Remediation

Organizations should monitor developments and apply any available patches as they are released. Additionally, it's advisable to conduct a thorough assessment of kernel configurations and operational practices to ensure compliance with security best practices.

For continuous security improvements, organizations may benefit from regular penetration testing. This can help identify weaknesses in their systems before they can be exploited.

Organizations should consider engaging in a penetration testing program to validate their defenses against potential threats.

Detection Guidance

Organizations should monitor log indicators for any unusual behavior that might suggest exploitation attempts. Additionally, behavioral anomalies in system operations should be flagged and investigated.

System changes that coincide with kernel updates should also be scrutinized to ensure that no unauthorized alterations have been made.

AppSecure Threat Intelligence Insight

The long-term significance of this vulnerability in the Linux kernel may highlight the need for enhanced validation practices in kernel development and deployment. Organizations should consider this incident as a reminder of the importance of rigorous testing and validation procedures to ensure system stability.

Security teams should take this opportunity to review their kernel configurations and ensure they are following best practices. Regular assessments can help identify areas for improvement and reduce the likelihood of similar vulnerabilities emerging in the future.

Organizations should prioritize continuous improvement in security practices, including engaging in penetration testing methodology to identify and mitigate potential vulnerabilities.

Overall, this incident serves as a critical reminder for organizations to stay informed and proactive in addressing vulnerabilities within their systems.