CVE-2024-50285 in Linux
Summary
by MITRE • 11/19/2024
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: check outstanding simultaneous SMB operations
If Client send simultaneous SMB operations to ksmbd, It exhausts too much memory through the "ksmbd_work_cache”. It will cause OOM issue. ksmbd has a credit mechanism but it can't handle this problem. This patch add the check if it exceeds max credits to prevent this problem by assuming that one smb request consumes at least one credit.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 07/16/2025
The vulnerability identified as CVE-2024-50285 resides within the Linux kernel's ksmbd implementation, which serves as an SMB (Server Message Block) server component enabling file sharing services. This flaw represents a critical memory exhaustion issue that can lead to system instability and potential denial of service conditions. The vulnerability specifically targets the handling of concurrent SMB operations within the ksmbd subsystem, where improper resource management allows malicious or malformed client requests to rapidly consume available memory resources. The ksmbd_work_cache mechanism, designed to manage SMB work items, becomes a critical point of failure when subjected to excessive concurrent operations, creating a scenario where system memory can be depleted to the point of triggering out-of-memory (OOM) conditions that may result in system crashes or forced reboots.
The technical root cause of this vulnerability stems from the inadequate handling of simultaneous SMB operations within the ksmbd server implementation. While the system does implement a credit mechanism to manage network flow control and resource allocation, this mechanism proves insufficient for preventing memory exhaustion attacks. The flaw occurs when multiple SMB operations are submitted concurrently by a client, causing the ksmbd_work_cache to rapidly consume available memory resources without proper bounds checking. The patch addresses this by implementing a validation mechanism that monitors credit usage and prevents operations from exceeding the maximum credit limit, assuming that each SMB request consumes at least one credit. This approach effectively limits the number of concurrent operations that can be processed simultaneously, thereby preventing the memory exhaustion that would otherwise occur. The vulnerability demonstrates a classic case of insufficient resource management and lack of proper rate limiting in network service implementations.
The operational impact of CVE-2024-50285 extends beyond simple denial of service conditions to potentially compromise entire system stability and availability. When exploited, this vulnerability can cause systems running ksmbd to experience sudden memory exhaustion, leading to OOM killer activation that may terminate critical processes or cause system-wide instability. Network administrators and system operators face significant risks when this vulnerability exists in production environments, particularly in scenarios where multiple clients connect simultaneously or where automated tools perform concurrent SMB operations. The vulnerability affects systems that rely on ksmbd for file sharing services, including network-attached storage devices, file servers, and any infrastructure that depends on SMB protocol implementations. Organizations using Linux systems with ksmbd services are particularly vulnerable, as the issue can be exploited by both malicious actors seeking to disrupt services and by automated tools that may inadvertently generate excessive concurrent operations.
Mitigation strategies for CVE-2024-50285 focus on implementing proper resource limits and monitoring mechanisms within the ksmbd configuration. System administrators should ensure that the kernel version includes the patched implementation that enforces credit limits and prevents excessive concurrent operation handling. The recommended approach involves configuring appropriate limits on concurrent connections and implementing monitoring to detect unusual patterns of SMB operations that might indicate exploitation attempts. Network-level protections such as rate limiting and connection tracking can provide additional defense-in-depth measures. Organizations should also consider implementing intrusion detection systems that can monitor for unusual SMB traffic patterns and alert administrators to potential exploitation attempts. The vulnerability aligns with CWE-400, which addresses uncontrolled resource consumption, and maps to ATT&CK technique T1499.004 for network denial of service attacks. Regular security updates and kernel patch management become critical defensive measures, while proper system hardening practices including limiting network exposure and implementing proper access controls further reduce the attack surface for this vulnerability.