CVE-2026-72178 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, DAMON subsystem users and administrators, security teams, and operators responsible for monitoring and maintaining Linux kernel-based systems. These individuals should be aware of the potential PID leak issue in the DAMON subsystem and take necessary steps to apply the patch and review their systems' configuration. They should also monitor for any unusual activity and review compensating controls for exposed systems while remediation is scheduled and verified. Additionally, they should track exceptions, retest remediated assets, and close the item only after evidence is documented. The vulnerability can have an impact on the security and stability of Linux kernel-based systems, making it essential for these individuals to take proactive measures to prevent exploitation. They should also review the Linux kernel's DAMON subsystem configuration and update it as necessary to prevent similar issues in the future. Furthermore, they should consider implementing additional security measures, such as monitoring and detection tools, to identify and respond to potential security incidents related to the vulnerability. By taking these steps, they can help prevent potential security breaches and ensure the stability and security of their Linux kernel-based systems. The vulnerability can also impact the overall security posture of an organization, making it essential for security teams to be aware of the issue and take necessary steps to mitigate it. They should also consider conducting a thorough risk assessment to identify potential vulnerabilities and develop strategies to address them. By doing so, they can help prevent potential security breaches and ensure the overall security and stability of their systems. In addition, operators responsible for monitoring and maintaining Linux kernel-based systems should be aware of the potential PID leak issue and take necessary steps to apply the patch and review their systems' configuration. They should also monitor for any unusual activity and review compensating controls for exposed systems while remediation is scheduled and verified. By taking these steps, they can help prevent potential

Technical summary

The vulnerability occurs in the damon_commit_target() function, which puts and gets the destination and source target PIDs. If the commit operation fails, the PIDs may not be properly put, leading to a leak. The fix involves putting the PIDs in the commit operation in case of failures. This is achieved by modifying the damon_commit_target() function to handle the PIDs correctly in case of failures. The vulnerability is related to the DAMON subsystem in the Linux kernel, which is used for data access monitoring. The issue can occur when committing target PIDs during a context commit operation fails, leading to a potential PID leak.

Defensive priority

Apply patch to prevent potential PID leak in DAMON context commit

Recommended defensive actions

• Apply the patch to the Linux kernel to fix the PID leak issue
• Review and update DAMON context commit operations to ensure proper PID handling
• Monitor Linux kernel updates for any related fixes or patches
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
• Review compensating controls for exposed systems while remediation is scheduled and verified.
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.

Evidence notes

The issue was discovered by Sashiko. The vulnerability is related to the DAMON subsystem in the Linux kernel. The commit feature is used to change parameters of a running DAMON context while inheriting internal status. To verify the vulnerability, defenders should review the Linux kernel's DAMON subsystem configuration and monitor for any unusual activity. The vulnerability is considered low-risk as it requires a specific use case and a large number of target regions. However, it is still essential to apply the patch to prevent potential PID leak in DAMON context commit. The patch fixes the issue by putting the PIDs in the commit operation in case of failures.

Official resources