CVE-2022-3646 in Linux
Summary
by MITRE • 10/21/2022
A vulnerability, which was classified as problematic, has been found in Linux Kernel. This issue affects the function nilfs_attach_log_writer of the file fs/nilfs2/segment.c of the component BPF. The manipulation leads to memory leak. The attack may be initiated remotely. It is recommended to apply a patch to fix this issue. The identifier VDB-211961 was assigned to this vulnerability.
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Analysis
by VulDB Data Team • 07/18/2026
The vulnerability identified as CVE-2022-3646 represents a memory leak flaw within the Linux kernel's NILFS2 file system implementation, specifically affecting the BPF (Berkeley Packet Filter) component. This issue resides in the nilfs_attach_log_writer function located in fs/nilfs2/segment.c, demonstrating how kernel-level memory management can be compromised through improper resource handling. The vulnerability's classification as problematic indicates its potential to cause significant system instability and resource exhaustion over time. The attack vector is remote, meaning malicious actors can exploit this flaw without requiring local system access, making it particularly dangerous in networked environments where kernel vulnerabilities can be leveraged for broader system compromise. The memory leak occurs when the kernel fails to properly release allocated memory resources during the log writer attachment process, creating a gradual consumption of system memory that can ultimately lead to system performance degradation or complete system hang.
The technical exploitation of this vulnerability stems from improper memory management within the NILFS2 file system's BPF implementation, which operates under the broader context of Linux kernel security architecture. The flaw demonstrates characteristics consistent with CWE-401, which addresses improper release of memory after transfer of ownership, indicating that the kernel's memory allocation and deallocation mechanisms fail to properly manage resources during the attachment process. This vulnerability directly impacts the kernel's ability to maintain stable memory allocation patterns and can be categorized under the ATT&CK technique T1059.001 for command and scripting interpreter, as exploitation may involve manipulating kernel memory structures through legitimate kernel interfaces. The remote exploitability suggests that attackers can trigger the memory leak through network-based interactions with the affected system, potentially using crafted BPF programs or file system operations that invoke the vulnerable function path. The vulnerability's impact extends beyond simple memory consumption, as it can contribute to system instability and may provide a foundation for more sophisticated attacks that leverage resource exhaustion to bypass other security controls.
The operational impact of CVE-2022-3646 presents significant risks to system availability and stability, particularly in environments where NILFS2 file systems are actively used. The progressive memory leak can cause systems to gradually consume available memory resources until system performance degrades substantially or system processes begin to fail due to insufficient memory. This type of vulnerability is particularly concerning in server environments where continuous operation is critical, as the memory exhaustion can lead to unexpected system crashes or forced reboots that disrupt services. Organizations using Linux systems with NILFS2 file systems are particularly vulnerable, as the flaw affects core kernel functionality that manages file system operations and memory allocation. The vulnerability's remote exploitability means that attackers can maintain persistent access to systems by continuously triggering the memory leak, potentially causing denial of service conditions that can be difficult to detect and remediate. The impact is amplified in virtualized environments where memory exhaustion on one system can affect the entire virtual infrastructure, making this vulnerability particularly dangerous in cloud and containerized deployments.
Mitigation strategies for CVE-2022-3646 should prioritize immediate patch application from trusted kernel vendors, as this represents the most effective defense against exploitation. System administrators should implement comprehensive monitoring of memory usage patterns to detect potential exploitation attempts, particularly looking for gradual memory consumption increases that may indicate the memory leak is active. The patching process should include thorough testing in staging environments before deployment to production systems, ensuring that the fix does not introduce regressions in file system functionality. Organizations should also consider implementing kernel hardening measures such as kernel address space layout randomization and memory protection mechanisms to reduce the effectiveness of potential exploitation attempts. Network segmentation and access controls should be enhanced to limit exposure of systems running NILFS2 file systems, particularly in environments where remote access is not strictly required. Additionally, regular vulnerability assessments should include checks for similar memory management flaws in other kernel components, as this vulnerability demonstrates how improper resource handling can lead to system instability. The remediation process should also involve updating system monitoring tools to detect anomalous memory usage patterns that may indicate exploitation, and implementing automated alerting for memory consumption thresholds that could signal the presence of the vulnerability.