Overview
CVE-2025-40229 describes a memory leak vulnerability discovered and fixed in the Linux kernel’s DAMON (Data Access Monitoring) subsystem. This vulnerability arises from incomplete cleanup during the destruction of a DAMON scheme, potentially leading to resource exhaustion over time. This article provides a detailed analysis of the vulnerability, its possible impact, and the necessary mitigation steps.
Technical Details
The vulnerability resides within the damon_destroy_scheme() function in the DAMON core. Prior to the fix, this function was only cleaning up the filter list associated with a DAMON scheme but neglecting to free the ops_filter. This oversight resulted in memory allocated to ops_filter not being released when the scheme was destroyed, leading to a memory leak.
Specifically, the patch ensures that both the main filter list and the ops_filter are properly deallocated within damon_destroy_scheme(), preventing the accumulation of orphaned memory.
CVSS Analysis
Currently, no CVSS score has been assigned to CVE-2025-40229. This is likely because the vulnerability is a memory leak, which typically does not offer immediate avenues for exploitation like remote code execution or privilege escalation. However, a persistent memory leak can degrade system performance and potentially lead to a denial-of-service condition if left unaddressed.
Severity: N/A
CVSS Score: N/A
Possible Impact
While not immediately exploitable for arbitrary code execution, the memory leak introduced by CVE-2025-40229 can have the following impacts:
- System Instability: Over time, the accumulated memory leak can consume available RAM, leading to performance degradation and system instability.
- Denial-of-Service (DoS): In extreme cases, the memory leak can exhaust system memory, causing the system to crash or become unresponsive, resulting in a denial-of-service condition.
Mitigation and Patch Steps
The recommended mitigation is to apply the patch provided by the Linux kernel developers. This patch ensures that both the filter and ops_filter are properly freed during scheme destruction.
To apply the patch, you can either:
- Upgrade to a kernel version that includes the fix.
- Apply the specific patch to your existing kernel. You can find the patch details in the references below. Recompile and install the kernel after applying the patch.
It’s crucial to regularly update your kernel to receive security patches and bug fixes, including this important memory leak fix.
References
Kernel Commit: Fix potential memory leak by cleaning ops_filter in damon_destroy_scheme
Kernel Commit (Related): mm/damon/core: fix potential memory leak by cleaning ops_filter in damon_destroy_scheme
