CVE-2018-5333 in Linux
Summary
by MITRE
In the Linux kernel through 4.14.13, the rds_cmsg_atomic function in net/rds/rdma.c mishandles cases where page pinning fails or an invalid address is supplied, leading to an rds_atomic_free_op NULL pointer dereference.
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Analysis
by VulDB Data Team • 09/14/2025
The vulnerability identified as CVE-2018-5333 represents a critical null pointer dereference flaw within the Linux kernel's Reliable Datagram Sockets (RDS) implementation. This issue specifically affects kernel versions through 4.14.13 and stems from improper handling of error conditions within the rds_cmsg_atomic function located in the net/rds/rdma.c source file. The RDS protocol is designed to provide reliable datagram communication over RDMA (Remote Direct Memory Access) networks, making it an essential component for high-performance computing environments where low-latency network communication is paramount. The vulnerability arises when the function encounters scenarios involving page pinning failures or invalid memory addresses during atomic operations.
The technical exploitation of this vulnerability occurs when the rds_cmsg_atomic function processes incoming messages without adequately validating the memory management operations that precede atomic operation execution. When page pinning fails or invalid addresses are supplied to the function, the error handling mechanism fails to properly check for null pointer conditions before proceeding with subsequent operations. This flaw falls under the CWE-476 category of NULL Pointer Dereference, which represents a fundamental programming error where a program attempts to access memory through a null pointer reference. The specific operational context involves the RDS RDMA subsystem where atomic operations are crucial for maintaining data consistency and integrity during high-speed network communication.
The operational impact of this vulnerability is severe as it can lead to system crashes or denial of service conditions within kernel space. When a null pointer dereference occurs in kernel mode, the system typically experiences a kernel oops or panic, resulting in complete system instability. This vulnerability is particularly concerning in production environments where the RDS protocol is actively utilized for high-performance computing clusters, database systems, or any infrastructure requiring reliable datagram communication over RDMA networks. Attackers could potentially exploit this flaw by crafting malicious network packets that trigger the page pinning failure conditions, leading to system crashes that would disrupt critical services and potentially allow for further exploitation in multi-stage attack scenarios.
Mitigation strategies for CVE-2018-5333 involve immediate kernel updates to versions that contain the appropriate patches addressing the null pointer dereference issue. System administrators should prioritize applying the latest security patches from their respective kernel maintainers, as this vulnerability has been addressed through proper error handling mechanisms that validate pointer conditions before dereferencing. Additionally, network administrators should consider implementing network segmentation and monitoring to detect anomalous traffic patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of robust error handling in kernel space operations, particularly for protocols that handle memory management and atomic operations. Organizations should also implement proper kernel hardening measures and consider using kernel address space layout randomization (KASLR) to make exploitation more difficult. This vulnerability aligns with ATT&CK techniques related to privilege escalation and denial of service within the kernel attack surface, emphasizing the need for comprehensive kernel security monitoring and proactive patch management strategies across all production systems utilizing affected kernel versions.