CVE-2026-64184 in Linux
Summary
by MITRE • 07/19/2026
In the Linux kernel, the following vulnerability has been resolved:
mm/damon/sysfs-schemes: call missing mem_cgroup_iter_break()
damon_sysfs_memcg_path_to_id() breaks mem_cgroup_iter() loop without calling mem_cgroup_iter_break(). This leaks the cgroup reference. Fix the issue by calling mem_cgroup_iter_break() before the break.
The issue was discovered [1] by Sashiko.
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Analysis
by VulDB Data Team • 07/19/2026
The vulnerability resides within the Linux kernel's memory management subsystem, specifically in the damon (Dynamic Access Monitoring) framework's sysfs interface implementation. This flaw affects the handling of memory cgroup iterations and represents a classic resource leak scenario that can lead to system instability and potential denial of service conditions. The damon framework is designed for monitoring memory access patterns and optimizing memory management, making this vulnerability particularly concerning as it impacts core memory management functionality.
The technical root cause involves improper cleanup within the damon_sysfs_memcg_path_to_id() function where the mem_cgroup_iter() loop termination does not properly release the cgroup reference. This occurs when the function encounters a condition that requires breaking out of the iteration loop without invoking the necessary mem_cgroup_iter_break() cleanup function. The memory cgroup iterator maintains references to cgroup structures that must be explicitly released to prevent memory leaks and maintain proper reference counting within the kernel's memory management subsystem.
This vulnerability directly maps to CWE-404, which describes improper resource release or unbalanced resource management in software systems. The operational impact extends beyond simple memory consumption as this leak can accumulate over time, potentially leading to exhaustion of available cgroup references and subsequent system instability. The issue becomes particularly problematic in environments with high memory usage patterns or frequent memory cgroup operations where the accumulation of leaked references can cause significant performance degradation.
The fix implemented addresses the specific programming error by ensuring that mem_cgroup_iter_break() is called before any break statement within the damon_sysfs_memcg_path_to_id() function. This approach aligns with established kernel development practices for managing reference counting and resource cleanup in iteration loops. The solution follows ATT&CK technique T1484.001 by preventing improper privilege escalation through resource exhaustion attacks that could exploit this memory leak.
From a security perspective, while this vulnerability may not directly enable arbitrary code execution or privilege escalation, it creates conditions favorable to denial of service attacks by consuming system resources. The leak could be exploited in resource-constrained environments where memory cgroup management is heavily utilized, potentially causing system instability or preventing legitimate memory management operations from completing successfully. This represents a critical issue for systems running intensive memory management workloads where the accumulation of leaked references can eventually impact overall system performance and stability.
The remediation approach demonstrates proper kernel memory management practices and emphasizes the importance of balanced reference counting in complex subsystems like memory cgroup handling. This vulnerability highlights the need for rigorous code review processes specifically focused on resource management patterns within the Linux kernel's memory subsystem, particularly in frameworks that interface with user-space through sysfs mechanisms where improper cleanup can have cascading effects on system stability and resource availability.